There are really three main ingredients in all (most) erasable whiteboard markers. Pigment, solvent, and a polymer.
1) Pigment
This is the actual color that you see. If it's a red marker, it'll have red pigment. A blue marker will have blue pigment. There are many different kinds of pigment, and many companies have patents on their own.
2) Solvent
This is what the pigment and the polymer are dissolved in. When you write with the marker, you may notice that it seems very wet and shiny at first. This is due to the alcohol. Within a few moments, the alcohol will evaporate, and you'll only be left with the pigment and polymer.
3) Polymer
The polymer is the 'glue' that holds the pigment to the board. The difference between dry-erase and permanent markers largely is due to the type of polymer used.
Hope that helps!
