Plastics News Europe - June 2019 - 14

automotive plastics

Honeycomb core panels offer
affordable lightweighting solution

t university, ThermHex/EconCore CEO Dr.-Ing. Jochen
Pflug, then a materials engineering student, became intrigued by
the possibilities of using lightweight
composite materials with a honeycomb structure in vehicles and aircraft.
This interest led first to a degree based
on research into continuously produced honeycomb core materials and
ultimately to the founding of EconCore and its subsidiary, ThermHex.
"We have developed a new generation of core materials for sandwich
construction based on an innovative
production process," said Pflug. "Until now, it was only possible to produce these honeycomb cores as a
batch, not in a continuous process."
The successful development of a continuous production process has established EconCore's production
technology for thermoplastic honeycomb core materials. The process involves first producing the honeycomb
core, which is followed by the in-line
bonding of the skins. The result is a
lightweight, stiff sandwich panel that
can be mass produced, easily and in a
cost-effective manner.

Organosandwich is suitable for structural components

"It's also a versatile process - different combinations of core and skin
materials can be used," he explained.
Possible thermoplastics used for the
cores range from PP, PE, PS and PET to
PA, PC, PPS and PEI. The cores can be
produced in different core thicknesses
and cell sizes. "However, cell size is
not the main factor affecting
strength," said Pflug. "The weight
specific strength is dependent on the
polymer properties."
What about recyclability? "It is
possible to use the same polymer for
the honeycomb cores and the skin
materials, making the sandwich panels easily recyclable," he said. In addition, ThermHex has now expanded its

Honeycomb core made of recycled PET

portfolio to include honeycomb cores
made of recycled PET (rPET), which
debuted at the JEC World in Paris,
France in March and were also showcased at PIAE 2019 in Mannheim.
The new cores, the result of two
years' development work, are produced in Halle, Germany, and will be
available starting in the autumn of
this year. They are suitable for use in
all the same applications as panels
made from virgin materials.
One of the main application areas
for the sandwich panels produced using ThermHex honeycomb cores is
transportation, which obviously, is a
sector that can benefit strongly from
the lightweight properties of these
materials. "Typical applications in cars
are trunk trim, underbody panels,
seatbacks and door panels," said
Pflug. "The application of these panels has benefits that include improved
thermal insulation and acoustic performance, as well as to lower CO2
emissions, and hence reduced environmental impact."
A recent development is the new
Organosandwich, also produced using the ThermHex process. Developed
in cooperation with the Fraunhofer

ThermHex's Organosandwich
material

Institute for Microstructure of Materials and Systems (IMWS) it consists of
two glass fibre reinforced polypropylene skins, each consisting of two layers of UD tape in 0°/90° and the polypropylene honeycomb core. The
in-line laminating process of thermoplastic composite skins onto the honeycomb core enables an optimum
connection between core and skins
while making it possible to produce
the cost efficient Organosandwich as
semi-finished product in mass production. The Organosandwich, which
can be shaped and functionalised by
injection moulding, is intrinsically stiff
and provides the rigidity and impact-resistant properties required for
the automotive industry. According to
Pflug, weight savings of over 80%
are possible compared to a conventional monolithic GF/PP organosheet.
"Because GF/PP-UD tapes are separated by the core, fewer layers are
needed for the same stiffness," he
explained.
The application potential for the
Organosandwich is considerable.
"Door modules, underbody panels
and other structural components can
easily be made from Organosandwich," said Pflug. "Even battery
housings in electric vehicles, as the
material can provide sufficient impact
resistance."
The response from the market has
been 'very good', said Pflug. The
ThermHex technology is licensed by
EconCore in countries around the
world and customers, both in the
automotive as well as other industries, have been quick to appreciate
the benefits of the honeycomb core
technology.
Organosandwich will also go into
series production in autumn 2019.

june 2019

Plastics News Europe - June 2019

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