JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014 - 34

technology

At the foundation
and future of prepreg technology

Hexcel's long history of weaving - stretching back into the 19th
century - combined with 80 years of resin formulation made it a
natural progression for the company to combine the two technologies into the ultimate high-performance composite materials
known as prepregs.

By
Thierry Merlot
VP & General Manager Europe
/ MEA / Asia Pacific
Hexcel

P

rior to prepregs, composite
structures were manufactured by
wet lay-up, combining resins and
fibres in a process that made it difficult
to accurately control and reproduce the
fibre content throughout a structure.
The development of prepregs, materials
supplied on ready-to-cut rolls where
the resin is pre-impregnated into the
reinforcements in very precise quantities
and partially cured (B-stage), was to
revolutionise the composites industry.
The first composite primary aerostructure was built at Hexcel's site in
Duxford, UK in August 1940. Due to
the threatened shortage of aluminium
during the Second World War, an experimental Spitfire fuselage was built using
"Gordon Aerolite" - flax linen roving
that was impregnated with phenolic resin and made into bands approximately
150 mm in width on a machine specially
developed for the purpose. To make
sheet material, a number of these bands
were placed edge to edge and overlaid by
others placed at right angles to build up

The first composite aircraft fuselage, built for a
Spitfire in 1940 by Hexcel's UK site

the required thickness. The pack of strips
was then hot-pressed to bond them into
a single sheet. Gordon Aerolite was used
for all the Spitfire structural members
including the frames, longerons and
stringers as well as the stressed skins.
Tests at the Royal Aircraft Establishment, Farnborough, showed that this
first fibre-reinforced composite structure
was as strong as the aluminium one that
it could replace "if it could be made
available in quantity".

submarines, aircraft (Canberra bombers
and Harrier jets), helicopters and racing
boats. In 1974, the prepregs were adhesively bonded to slices of honeycomb to
form the first entirely composite floor
panels for the Boeing 747.
But it wasn't until the development and
industrialisation of carbon fibre in the
late 1960's that prepreg became a serious
contender for manufacturing even more
efficient and lighter structures, with
greater strength, stiffness and durability.
The "advanced composites" era had
begun.
Hexcel introduced carbon fibre-reinforced composites to the aerospace
industry in the early 1970's, supplying
prepregs for the A300 spoilers and
fairings, followed by the 10-m-high

First commercial prepregs
Hexcel's first commercial prepregs of the
late 1960's and early 70's were reinforced with glass fibre and supplied for

34 jec composites magazine / No86 January - February 2014

With the introduction of carbon fibre the
"advanced composites" era had begun
JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014

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