Automotive interiors typically contain flexible polyvinyl chloride (PVC), from instrument panels to faux leather. Over the years, a hazy film appears on the inside of car windshields; this is what is referred to as fog. As described in SAE J1756, fog is the tendency of interior materials used in automobiles and other vehicles to produce a light scattering film on glass surfaces.
What changes in the automotive industry have driven the need for fog testing and the reduction of SVOC outgassing?
Closed cars (1930’s)
-Open cars had allowed any VOC gasses to escape
-Closed cars also increased the interior temperatures
Vinyl use in interiors (late 1950’s)
-As more and more plastics get used in automotive interiors, more VOC gasses are released
Air conditioning (1980’s standard equipment on most cars)
-With air conditioning more owners drive with their windows up
Improved sealing (mid 1990’s)
-Fewer places for VOC gasses to escape on their own
-Improved seals also emit VOC gasses
Xenon Headlights (2000’s)
-Operate at high temperatures that heat surrounding polymers
-SVOC’s can coat the inside of the headlight lens reducing and scattering light output
