Spring 2002 Vol. 4, No. 1

Montan Waxes are vegetable fossil waxes that are derived from wax-rich lignite and peat. These original raw materials have to be extracted, de-resinified and oxidized. The resulting product is a so-called Montan Wax Acid, a pale yellow wax that can be, among other things, esterified. Basically, Montan waxes consist of a carbon chain length between 24 and 32 and have acid values between 15 and 140 mg KOH/g.

One of these Montan waxes is Ceridust 5551, a micronized ester wax with an acid value of 15 mg KOH/g and an average particle size diameter of 8.5 µm. The drop point, or melting point range, is between 95°C and 101ºC.

This unique chemical composition results in interesting applications in the manufacture of powder coatings. As the wax is much more polar than even oxidized polyethylene waxes and contains carboxylic and ester functional groups, it exhibits an excellent tolerance of the resins used in the manufacture of powder coatings. This property leads to an increase of up to 30% in the throughput in the extrusion process. This could be proved by trials using a hybrid system, both by the reduction of the power consumption and by the above-mentioned measurement of the feed rate.

Additionally, this product facilitates pigment dispersion due to its low melting viscosity (25mPa.s at 120ºC) and excellent pigment wetting properties. Tests have shown that the color strength is increased by up to 30% when the dosage of the wax on total formulation is 2.0%. Ceridust 5551 thus continually facilitates pigment wetting and dispersion.

The preceeding graphs show the effect of several wax concentrations on pigment dispersion and extruder throughput rates for a hybrid powder coating.