The use of Fischer Tropsch waxes in processing of PVC & CPVC -3

5. Oxidized F. T. Waxes:

Oxidized Fischer – Tropsch wax is made by oxidation of Fischer-Tropsch wax.

Compared with Fischer-Tropsch wax, oxidized Fischer – Tropsch wax has higher hardness, moderate viscosity, and better colour. It is a very good lubricant material.

Blends of Fischer-Tropsch hard waxes are manufactured to produce highly efficient waxes for PVC, having a good balance of properties.

This enables the formulation of a suitable wax requiring lower levels of oxidation, thus enabling some compatibility with the polymer while still achieving high levels of external lubrication.

It also helps to balance internal and external lubrication, making it an advantageous alternative to PE wax.

It has good compatibility with PVC and can effectively control shear conditions, promote flow, control friction, and melt properties.

Thus, it helps to improve thermal stability.

The viscosity of melted oxidized Fischer Tropsch wax is generally lower than that of Fischer Tropsch wax.

6. Use of F. T. Waxes in PVC & CPVC processing:

Fischer-Tropsch wax can be applied to PVC processing, such as injection moulding, extrusion, and pelletizing.

Fischer – Tropsch waxes help to disperse fillers and provide excellent slippery properties during compounding in the production of masterbatches and modified plastics.

It can be used as an external lubricant for PVC, where its low viscosity can improve the production speed of the product.

It can help to disperse pigments and fillers during mixing. It has a better use in the extrusion of high viscosity systems and can significantly improve the surface gloss of products (can replace carnauba wax).

When using strong colours, melted Fischer – Tropsch wax can effectively wet the dye and reduce extrusion viscosity.

F. T. waxes exhibit good dielectric constant, electrical resistance, and electrical breakdown strength that is superior to those of the petroleum waxes and are preferred as lubricants for wire and cable applications.

The extent of die swell is inversely proportional to the doses of non-polar lubricants. F.T. waxes being highly efficient provide lower pressure and reduce die swell.

In CPVC processing, judicious combination F. T. waxes and PE waxes give better results in terms of reduced die swell and reversion.

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