Plush interiors, replete with cushy synthetic fabric seats and soft vinyl dashboards, are hot sellers in automobile showrooms. Perhaps only leather now surpasses plastic in its level of aesthetic refinement in cars.
But what about that putrid vinyl gas?
As many new-car buyers find out, the huge amount of plastic in automobile interiors can emit chemicals that not only smell terrible but also deposit oily films on interior windows.
Many new car owners complain about a stubborn deposit of film that builds up on the inside of the windshield. No amount of glass cleaner seems to keep the film from forming. The problem is not that the glass cleaner is failing to remove the film, but rather that a new deposit of vinyl film forms after awhile.
Soft vinyls can be composed of up to 50% plasticizers, which are chemicals added to standard polymers that make them soft. Lots of vinyls contain plasticizers, but inside a car they pose a special problem.
A car parked in the sun can reach temperatures above 120 degrees, hotter than the volatility point of plasticizers. When the volatility point is reached, molecules of the plasticizers become gaseous and then condense on the coolest surface. Typically, that includes the windshield.
Auto makers have worked hard to minimize the problem. Some firms have reduced the amount of soft vinyl in their interiors and have gone to harder plastics, such as polycarbonates. Ford, for example, sometimes uses blends of ABS plastics, a particularly hard substance often used for telephones. Another trick auto makers are using to reduce vinyl gas is putting a clear top coat over the vinyl.
Along with reducing vinyl gases, auto makers have also reduced the tendency of interior plastics to crack apart with age. Intense sunshine is a demon to plastic dashboards, but newer plastics are easily withstanding eight years of ultraviolet attack.
Even with all the improvements, some vinyl gas still gets deposited on almost all new car windshields. As a car ages, the plasticizers evaporate away and the vinyl stops emitting gas.
If you park your car in a garage, you could also leave the windows open to help minimize the problem. Finally, almost all vinyl gas deposits clean up quickly with window cleaners, but getting rid of streaks often takes a second cleaning.