Industry considers a wax to be fatty solid with varying degrees of lubricity and plasticity.
The technology in the coatings and ink field has grown over the years and the wax industry has changed with it.
Natural waxes were first used in coating and ink industries. natural waxes may of vegetables, animal origin. The most prevalent of these waxes is Carbauba, which is still widespread in use. Carbauba wax is obtained from the leaves of a species of palm.
When less expensive petroleum waxes became suitable, formulators discovered new characteristics which made these waxes unique among raw materials. Paraffin is obtained from the wax tailings remaining in the stills after the distillations of pure petroleum. Paraffins quickly became the additive of choice and entered into the greatest variety of formulations than any other waxes.
Micro crystalline waxes also belong to this class. These are obtained by dewaxing heavy lubricating oils and petroleum residues. Over the years, many of the so-called synthetic waxes entered the market. Most prevalent of these materials are Fisher-Tropach waxes.
More recently, the waxes of choice are Polyethylene waxes, with molecular weights of 1000 to 3000, odourless, tasteless and nontoxic. Today, Polypropylene waxes with melt points around 1500+C are being used in high bake and low gloss applications.
The use of synthetic waxes have become much more widespread over the past two decades with the advances made with micronising techniques.
One of the main Wax types used today are the low molecular weight polyethylenes both homopolymers and their partially oxidised derivatives. Low molecular weight would be defined by a number average ranging from 2000 to 5000 approximately. This level is, of course, considerably higher than paraffins, microcrystallines and F-T Wax. This difference renders them tougher and this in conjunction with their varying hardness and slip characteristics makes them ideal additives in inks and coatings. Use level could be roughly described as concentrations ranging from 0.25 to 5% on solids.