We bought a new car a little over a year ago, and while choosing what make of car to purchase naturally took weeks of research and consideration, it took us almost as long again just to decide on what colour of car we wanted. (We settled on “platinum green.”)
Painting an automobile involves many coats of paint, starting with an initial “electrocoat” designed to bond well to bare metal; that’s followed by a primer, which provides a smooth base for subsequent coast, a colour coat, which may also provide special effects such as a metallic sheen, and a clear coat that keeps everything shiny.
All of these layers currently involve solvents–very high levels of solvents, in fact; in standard base coats and clear coats, the solids content is only 12 to 30 percent. All these solvents find their way into the atmosphere–the more so because car paint is dried in huge ovens through which large amounts of air are forced to keep the amount of solvent vapour in the air from reaching the explosive level–contributing to air pollution. In fact, these evaporating solvents (called volatile organic compounds, or VOCs for short) constitute the largest single source of air pollution at any automobile manufacturing plant.
Not only that, but even with advances in spray painting in the past few years, only 40 to 45 percent of the paint sprayed actually adheres to the car; the rest escapes, again contributing to pollution. Other environmental costs to the current method of painting cars include the large amounts of energy needed to produce the solvent in the first place and the energy needed to run the drying ovens and fans.
Steps are being taken to improve this situation. Work is being carried out to develop water-based automotive paints with higher solids content and only minimal amounts of solvent that provide satisfactory results with just a single application. This would not only reduce the amount of VOCs produced by the painting process, it would speed it up, which in itself would reduce energy consumption. As well, the drying ovens could be run at lower temperatures.
But there may be an even better solution on the horizon; a new technology that could eventually do away with the use of paint on automobiles altogether (provided, that is, that those automobiles are made of plastic, not metal!).
It’s called Sollx, and it’s a .5-millimeter-thick polymer film developed by General Electric. Plastic covered with Sollx looks like freshly painted metal, comes in a variety of colours, and is more resistant to scratches and chemicals than paint.
The Segway scooter has Sollx-covered wheels. Sollx will eventually find its way onto all sorts of devices, but GE thinks its most profitable market will be the automotive industry, where Sollx will probably first be used as a finish for small plastic components such as the housings for side-view mirrors, but could eventually coat entire vehicles.
Paint, besides causing environmental problems, is the auto industry’s single biggest manufacturing expense: the paint facilities of a car factory can cost as much as $400 million U.S., a third of the cost of the entire factory.
Car designers have been using more and more plastic on cars recently: the VW Beetle has plastic fenders, for example, while the Saturn has plastic doors, and most cars have plastic covering their bumpers. Plastic can be shaped more easily than metal and it reduces the car’s overall weight, improving fuel efficiency and acceleration. Sollx could help make plastic even more attractive to designers, and acceptable to consumers.
GE is working on making Sollx-coated plastic look indistinguishable from painted metal, so that plastic fenders and other parts can be better integrated into cars that mix both plastic and metal (it’s not that it’s hard to make Sollx-covered plastic look as good as painted metal; the problem is it looks better than painted metal, so they’re actually trying to introduce some imperfections into its appearance so it will blend in better).
GE even says the material is theoretically capable of being designed to change color as the temperature changes, so your car might turn from a dark color in cold weather to a lighter one in hot weather.
In the ’70s, we wore mood rings. In a few more years, we may be driving them.
