How car colours are going 'green' with help of new tech

By dpa | 14 March 2023


LAS VEGAS/BERLIN: BMW has come up with a concept car that can change colour by remote control and VW recently chose the garish Las Vegas boulevard for the world premiere of its ID.7 electric which wore a QR code-style coat of many colours.

It seems manufacturers are finally shaking up the world of car colours after decades of boring blues, greys, tans, taupes, whites, off-whites, charcoals and blacks.

After all, paint is one of the most important design aspects of a car — the right paint job can mean the difference between luxury or a dowdy SUV. It also can turn an old banger into a dream machine for teens.

Sustainability is a new watchword in the world of car paint and it seems carmakers have adapted Henry Ford's legendary “you can have any colour as long as it’s black” to mean green instead and now offer a huge range of eco-friendly hues.

Car coatings have always been driven by technology and the new variable ones showcased by BMW and Volkswagen are the result of chemical advances.

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Most VWs come these days in discreet shades of grey but the Wolfsburg company opted for a riotous splash of colour, applying more than 40 different layers of paint to the ID prototype, some of which were made to glow electrically. That turned the car into a chameleon among the electrics.

"The palette on our roads is definitely becoming more colourful again," says Mark Gutjahr, who is charge of design at supplier BASF Coatings in Münster.

"With the increasing electrification of the car, more and more models are vying for attention and numerous new manufacturers are also coming into play. This is reflected in the colour spectrum," said Gutjahr. He said colour consultants are recommending makers to offer hues at the bolder end of the spectrum.

Looked at one way, there is actually only one trend colour at the moment, at least in the figurative sense, and that is green, whether as a pastel or traditional shade, muted or screamingly colourful.

"In the quest for the smallest possible carbon footprint and ultimately climate-neutral production, the focus is increasingly on 'green' coatings," said Marco Benen from Sustainability Management at BASF.

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The trend poses a challenge to industry which can hardly avoid using chemicals made from fossil-fuels. Only a few ingredients can be replaced by renewable raw materials, said Benen.

Coatings can be made more eco-friendly by shortening supply chains, making energy processes more efficient and by cutting the use of CO2 during manufacture.

Almost more important than the components of the paint, however, is how it is processed, the expert says. The different layers have to be literally baked onto into the sheet metal in the paint shop of the car factory and that uses a lot of energy.

"If one layer can be spared or the process temperature is lowered by a few degrees, significant amounts of CO2 can be saved over the year," said Benen.

Another contribution to sustainability are paint layers that can repair damage themselves. Small scratches vanish like magic under the rays of the sun, meaning not every damaged body part has to be repainted, said BASF expert Matthijs Groenewolt, who researches into clear coatings.

That saves the customer money and the prevents further CO2 discharge into the environment.

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Michaela Liese from the Color Center Europe pointed out that certain colours are good too for cars with driver or robot assistance on board.

Robot cars vehicles rely on lidar, radar and cameras and highly-reflective surfaces are more easily detected by these systems which allow the autonomous vehicles to determine the distance from a laser emitter to an object or surface using a pulsed beam.

Research focuses on special paints that enhance these signals. Whites are much better than black and grey coatings which absorb a greater amount, reducing the reflected signal strength by 50% compared to white cars.

"And ideally, of course, a paint fulfils both properties, because every transmitter vehicle can also be a receiver and vice versa," said the expert.

VW was not alone in playing with colours at the Las Vegas CES tech fair at the start of the year. For the second year now, BMW came with a show car that uses e-ink technology familiar from e-books.

Last year they could only alternate between black and white but this time the experience is also available in technicolour - and in almost three dozen different shades and even more patterns.

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"The response was so overwhelming that we wanted to continue down this path," said project manager Stella Clarke. "Just as you choose your clothes in the morning according to your mood, you can also change the colour of your car according to your mood and make the car an expression of your personality."

Sustainability is naturally an issue here too, said BMW's development head Frank Weber: "The advantage of e-ink technology is that the colour change is virtually free of charge in terms of energy: We only need electricity to switch, then the new colour stays by itself. Whether lemon yellow, aubergine or strawberry red."

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