These are highly effective external lubricants for PVC, with a positive effect on gelation and surface quality of finished products. Polar polyethylene waxes have a pronounced anti-sticking effect and high molecular types are suitable for transparent items. Other waxes improve pigment dispersion and permit the production of highly concentrated masterbatches with better color yield. Montan waxes are excellent lubricants for many thermoplastics and thermosets. They are mainly used in PVC, where they have wide-range internal and external lubricating effects and worldwide approval under food legislation. The property profile of waxes in PVC is characterized by a high anti-sticking effect and good flow improvement. In contrast, lubricants based on fatty acids do not affect melt strength or Vicat softening point. They are compatible with other components even when added in large quantities. They are particularly suitable for critical processes making high demands on the lubricant, such as the production of a calendered film, blow-molded articles, and products stabilized with calcium/zinc. They give good release properties with engineering plastics.
Wax classification
A wide variety of wax materials are available, either naturally or synthetically, with varying physical and chemical characteristics.
Generally, microcrystalline waxes have the highest melting points, as they have a higher molecular weight. Wax chain morphology varies significantly depending on its source and processing, resulting in a wide range of waxes from hard materials with high melting points (up to 900 C) to softer and more flexible types (melting points (up to 65 C).
In comparison to paraffin waxes, microcrystalline waxes have longer chains and irregular molecular structures. The irregularities in the wax, therefore, affect its crystallinity, size, and degree of crystallinity. This morphology greatly influences the final flexibility of the product, which has a wide range of applications due to its material properties.
There are fewer irregularities in the molecular chain of paraffin waxes and their structure is highly linear. Consequently, paraffin wax crystallizes rapidly. Pure normal paraffin is generally stiff and brittle, resulting in high gloss, an excellent moisture barrier, and fast congealing characteristics. Carbon chain length will generally vary depending on where the crude was sourced.
This includes waxes that do not fit into the definition of paraffin or microcrystalline wax. The melting point, viscosity, and crystallinity balance of waxes in this category can vary tremendously.
Application of Wax
Polyethylene wax, ethylene copolymer wax, and oxidized polyethylene wax are all helpful for maximizing pigment efficiency. Based on the specifications for the final product:
Reduce pigment concentration,
or reduce the amount of shear force required.
During extrusion or molding, act as a lubricant
