Evonik Offers Scratch Resistant Automotive Clearcoats

Evonik Industries is paving the way for a new technology whose
applications include automotive finishes that are more scratchresistant
than ever before. The specialty chemicals company has
developed an industrial-scale method for producing silanemodified
binders for automotive finishes. The advantage of these
silane-modified binders: silane groups increase crosslinking
density, making it possible to create automotive finishes that are
flexible yet harder, leading to improved scratch resistance.
The basic concept behind the new technology was already known:
modifying classic binders with silanes noticeably improves the
binder properties. This also applies to the polyurethane binders
typically used for automotive finishes. Up to now, however,
production of silane-modified polyurethane binders has been so
complex and expensive that these products have only been made
on a small scale for applications such as high-performance
adhesives. For more general uses and for large-scale applications
such as automotive finishes, however, there simply has not been
enough available. 

Gerd Brand, head of the Crosslinkers Business Line within the
Coatings & Additives Business Unit at Evonik, says: “The key factors
in our success have been Evonik’s comprehensive expertise in
silane and isocyanate chemistry, our understanding of the market,
and our intense collaboration with prominent players in the
automotive and coatings industries.”

The breakthrough came when the specialty chemicals company
developed its own manufacturing process for the silyl isocyanate
IPMS, or (3-isocyanatopropyl) trimethoxysilane. It is the critical
building block for producing silane-modified binders. Evonik has
been producing IPMS in a new facility in Marl (Germany) since mid-
2013. Dr. Ulrich Küsthardt, head of the Coatings & Additives
Business Unit at Evonik, points out: “With the new facility, Evonik
creates its access to IPMS and to a new group of customized,
silane-modified binders.”

By using IPMS and selecting the right additional raw materials,
Evonik can adapt coating binders to the needs of its customers.
Evonik, in other words, can provide coating formulators with
binders tailored to their final applications.

One of the first applications for the new IPMS binders is the thin
clear coating—only about 40 micrometers thick—that serves as the
glossy top layer of an automotive finish. In addition to improved
scratch resistance, the new systems are just as resistant to
chemicals and the elements as traditional two-component
polyurethane coatings. Plus, silane-modified binders are
completely compatible with two-component polyurethane coatings
and significantly improve their properties. For car manufacturers,
that means being able to use their usual production lines for
applying coatings that contain the innovative binder. Selected
automakers have already taken the first steps toward approving
clear finishes that have been modified in this way.

Dr. Hans Görlitzer, however, who works in the Coatings & Additives
Business Unit at Evonik as head of business development in the
Crosslinkers Business Line, believes the new technology has even
more potential: “We aim to open up access to silane-modified
binders for other applications too.”