| Soya beans are set
to become an important feature of car interiors. Suppliers are developing
new seating foams derived from soya oil that benefit the environment and
limit their exposure to volatile crude oil prices.
Cars use an average of 14kg of PU foam. International production consumes
more than 4 million tonnes, derived entirely 100 per cent from petroleum-based
polyols.
Ford estimates mass produced soy-based foams could realise annual material
cost savings of up to $26 million.
Interior supplier Lear has developed a polyurethane (PU) foam that uses
a 40 per cent blend soybean oil-based polyol in its manufacture. Johnson
Controls has a five per cent blend.
Polyols are one of the major constituents of PU materials
– typically 60 per cent. They are usually derived from petroleum
products. Oils from renewable sources offer clear environmental benefits.
According to the US National Institute of Standards and Technology, soya
polyols have only one-quarter the level of total environmental impact
of petroleum-based compounds.
In 2003 Ford was the first OEM to show that soya-based polyols could be
used at high concentrations – around 40 per cent – to meet
or exceed automotive requirements.
“For the time being, performance suffers if you exceed that level,
which is why 100 per cent soy-based polyols are not yet available,”
said Lear.
In the past, the material’s biggest drawback was its pungent smell.
Ford has patented a low temperature UV synthesis process that prevents
the 40 per cent blend from smelling.
Ford and Lear formed a partnership in 2004 to commercialise soya foam
applications, initially focusing on headrests and armrests. “Our
testing has proven SoyFoam will withstand a mass production environment
and meet performance requirements,” said Ash Galbreath, Lear’s
director of environmental comfort engineering.
Lear is also working with the United Soybean Board’s new uses committee,
Urethane Soy Systems, Bayer and Renesol Corporation on further development
of SoyFoam.
Johnson Controls has developed foam pads for car seats comprised of five
per cent soya-based products and 95 per cent polyurethane. The material
will feature on several new vehicles in 2007.
The performance requirements for seat cushions and seat backs are higher
than for head and arm rests, but the cost benefits are greater, said Johnson
Controls.
The firm’s five per cent blend may use less soya oil, but it could
save more petroleum overall. A typical complete set of seats for a vehicle
contains around 1.2kg of polyurethane material for seat cushions and seatbacks
compared to 0.16kg for head and armrests.
“Adding the soya does not affect the product’s performance,”
said Johnson Controls’ engineering vice-president Charlie Baker.
“But unlike petroleum, soya and other plant-based products are abundant,
renewable, and tend to have more stable market pricing.”
Johnson Controls moulds more than 43,000 tonnes of polyurethane foam annually
for the North American market alone. The soya will marginally reduce the
firm’s exposure to fluctuating oil prices.
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