i+D - September/October 2018 - 43

Making Use of Every Molecule - By Emileigh Clare and Todd Sims

Covestro research has proven CO2
offers an alternative and plentiful
carbon source for the production
of flexible polyurethane foam.
(Image: Covestro)

Berit Stange, PhD,
Covestro
(Image: Covestro)

Transforming CO2 into
Sustainability
Covestro AG, one of the world's leading manufacturers of
high-tech polymer materials, is pushing a new perspective within
the industry, by demonstrating how carbon dioxide (CO2), a main
contributor to global warming, can be captured and used for good.
Experts have been searching in vain for nearly half a century
to solve this scientific challenge, according to Berit Stange, PhD,
venture manager at Covestro. Now, thanks to a breakthrough
technology, the inert carbon dioxide molecule can be put to
practical use, creating flexible polyurethane foam that can
be employed to make sustainable mattresses and furniture.
"For many years, we have known that CO2 is one of the
primary greenhouse gases emitted into the Earth's atmosphere,
but there hasn't been a practical way to use it," explains Stange.
"By reducing our dependence on nonrenewable feedstocks,
CO2 gives us an alternative-and plentiful-carbon source for
polyurethane production." While flexible polyurethane foam is
not a new material to interior designers (it is commonly used in
upholstered furniture, bedding, and carpet underlay), it has not
been widely made with CO2 until now.
To start, chemists at Covestro discovered they could manufacture
a CO2-based polyol-later branded as cardyon-to create
polyurethane flexible foam. Traditionally, polyurethane flexible
foam is made using a variety of raw materials, including polyols
that react with isocyanates to create flexible polyurethane foam.
Chemistry and collaboration were critical to discovering that the
polyol portion of polyurethane could be made with CO2.
"There were a lot of challenges in the process," recalls
Stange. "Because CO2 is an inert molecule, it typically
requires a large amount of energy to make it react. However, if
more CO2 is generated at the end of this process than is saved
by incorporating it in the first place, the result would be neither

i+D - September/October 2018

ecological nor economical. We needed to find a suitable
reactant and the right catalyst to activate the CO2 without
generating more."
Once scientists made this discovery, the research and
development phase for the chemistry began. At the time,
Covestro operated a pilot plant in Leverkusen, Germany,
sourcing CO2 from an adjacent power plant. The team
manufactured CO2-based polyols for testing, until achieving
the desired quality in terms of softness and comfort.
Presently, CO2 content in the cardyon polyol grades are up
to 20 percent. Not only is the resulting foam comparable to
conventional foam, but the use of CO2 in polyurethane foam
production benefits the environment by reducing the overall
carbon footprint and establishing an alternative carbon source
beyond fossil hydrocarbons and bio-based raw materials.
According to Stange, the new material is a valuable resource
that can give interior designers a new, innovative option
to consider when designing for clients who want to live a
certain lifestyle. "You can sleep soundly knowing you're doing
something good for the planet," she adds. "And, for those in
the business of chemistry, CO2 is no longer the enemy; it's
part of the solution for more sustainable materials."
Currently, the cardyon polyol for flexible foam production
is commercially available on the European market, and
several other cardyon grades are available for thermoplastic
polyurethanes and coatings. Covestro has additional R&D
projects underway to use CO2 in many different types of
plastics, including rigid and molded foams and elastomers.

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