These are compounds to facilitate the coloring of a wide variety of plastics, the pigment being bound up in a concentrated form as an easier to handle and non-dusting form. Which
facilitates dispersion in many plastic compounds. The pigment loading can be as high as 60% for inorganics (which are easier to disperse), and 25 – 50 % for organic pigments and carbon
black
Concentrates are normally composed of a carrier polymer of either the same type as that to be colored, or of a type which has good compatibility with the one to be colored. This is
important because if the polymers are not compatible with each other, there is a diminution of the mechanical properties of the finished article. The other components are the pigment and
a wax.
There is a multitude of formulations, each with different ratios, depending upon the production method, specific pigment structure and known degree of difficulty in dispersing. With these
variables in mind, the amount of wax which is employed can range between 5 – 20%, though the norm is around 5 – 10%. Normally, the concentrate can be let down to color in levels from 1-5
%. Thus, the quantity of wax in the final article falls between 0.2 – 0.5%, when it is not detrimental to the mechanical properties.
The Marcus homopolymer polyethylene waxes, being of a chemically inert character and possessing excellent thermal stability and low melt viscosity, are well suited for the production of
these concentrates, not onl for the coloring of polyolefins, but also for a broad spectrum of other polymers. Their low melt viscosity results in excellent wetting out of the pigment,
which together with the high shear forces developed during processing, results in the breaking down of pigment agglomerates. This subsequently results in a very efficient and uniform
distribution of the pigment throughout the polymer being colored.