Currently there are two primary types of sealcoating materials on the market: Those made from refined coal tar and those made from asphalt. Refined coal tar —a byproduct of the coking process— is a very complex mixture of thousands of chemicals and quite different in its molecular structure than asphalt. The coal tar molecules have a predominantly closed ring (aromatic) structure with a minor degree of un-saturation. Being stable in molecular structure, these chemicals do not allow the destructive elements of weather and chemicals to affect the property of coal tar. So for a variety of reasons, the most commonly used sealcoatings have, until recently, been based on refined coal tar. These sealcoatings act as “barrier coats” to protect asphalt surfaces.
