What exactly makes permanent markers permanent? A marker is
considered permanent if it either sticks to most
surfaces, is water resistant, or uses dyes or
pigments. Permanent markers contain three main
ingredients: a colorant, a carrier, and a resin.
colorant, usually dyes or pigments, is what gives
markers their permanence, and, of course, their
colour. A dye is usually a coloring material
dissolved in water (or a solvent), making it a water soluble dye.
On the other hand, a pigment is an insoluble colouring matter. Pigments are also finely ground
solid materials and the amount as well as the nature
determines its colour.
Solvents are used as the carrier in permanent
markers. Before the nineties, most markers were made
out of a foul smelling hydrocarbon organic chemicals, like xylene.
Although these chemicals provide a desirable
permanancy, they are highly toxic. Today, xylene may be used in some markers
(e.g. Sharpie King Size), but most markers are now replaced
with an alcohol solvent. Alcohol, such as ethanol or isopropanol, is more environmentally friendly
and even smells better. It
also evaporates quickly, allowing permanent markers
to dry faster.
The last component, resin, is a polymer that
promotes adhesion. This also adds to the permanence
of markers. The resin sticks like glue to most of
the surfaces the marker is written on causing the
pigment to attach to surfaces. As a result, everyone
can easily write smoothly and clearly on both
rough and smooth surfaces.