Issue 02/2019

Applications
Multiwall sheet applications
E
xotic fruits, flowers, fish – there is a broad selection
of these in our supermarkets. For this variety,
fresh food has to be transported safely over long
distances. Transport boxes made of hollow-chamber multiwall
sheets are particularly suitable for this. They resemble
corrugated cardboard boxes but are waterproof. Until now,
multiwall sheets could not be made from bioplastics. Together
with international partners, the Fraunhofer Institute
for Environmental, Safety and Energy Technology UMSICHT
has now developed a biobased and biodegradable material
that can withstand the complex requirements in sheet production
and replace fossil plastics in the future.
Currently, multiwall sheets are manufactured from fossilbased
plastics, mostly polypropylene (PP). An alternative
based on renewable raw materials comes from Fraunhofer
UMSICHT. The researchers have developed a tailor-made
blend of bioplastics with similar properties to the PP blend
to be replaced. The sheets made of the new material are
lightweight and yet highly resilient. Unlike corrugated
cardboard boxes, they are waterproof, water resistant and
easy to clean.
The challenge of profile extrusion
Bioplastics blends available on the market have so far
not been suitable for demanding profile sheet extrusion
processes. It was a breakthrough when material properties
were improved and processing behavior was adapted by
developing a specific PLA-based formulation. “Particularly
challenging was the high complexity of industrial profile
extrusion,” explains Sengül Tolga, Department of Biobased
Plastics at Fraunhofer UMSICHT, who was one of the
researchers responsible for material development. “Our
research also focused on the cost-effectiveness of the
new material. Thus, we only used commercially available
bioplastics and additives,” adds Hendrik Roch, also from
the Biobased Plastics Department.
The scientifically substantiated material development
comprised of systematic investigations of the relationships
between composition, melt properties and processing of the
blend. The works took place at the Fraunhofer UMSICHT
Plastics Technology Center in Willich, which is specialized
in such bioplastics projects. For testing the processing of
the new material, first demonstration experiments were
carried out at a pilot plant (sheet width 450 mm) situated
in the premises of a renowned manufacturer of hollowchamber
profile tools.
The project concluded with a successful pilot test in
industrial scale (sheet width 2500 mm) at a Colombian
partner company. The multiwall sheets manufactured can
be used, for example, for the production of transport boxes
for the export of flowers, perishable fruit or fish. In addition,
the new material is to be developed further for other
applications in the floriculture and horticulture sector.
Successful international cooperation
The material development was part of a research project
within the Bioeconomy International Programme of the
Germann Federal Ministry of Education and Research
(BMBF). Under the leadership of Fraunhofer UMSICHT,
four partners from Germany and Colombia shared their
knowledge and experience in order to jointly develop the
multiwall sheets made of bioplastics:
• Fraunhofer-Institute for Environmental, Safety, and
Energy Technology UMSICHT, Oberhausen, Germany
• Instituto de Capacitación e Investigatción del Plástico y
del Caucho (ICIPC), Medellín, Colombia
• FKuR Kunststoff GmbH, Willich, Germany
• Compañía de Empaques S.A., Medellín, Colombia.
The combined expertise of the two research institutes
Fraunhofer UMSICHT and ICIPC was of great value for
the development of this innovative bioplastic for use in
the demanding industrial extrusion of multiwall sheets.
The close cooperation with the industrial partners made it
possible to realize a quick and practical implementation. MT
www.fkur.com | www.umsicht.fraunhofer.de
Transport box made of multiwall sheets produced from bioplastics
Multiwall sheet extrusion line
bioplastics MAGAZINE [02/19] Vol. 14 35