Polymer Additives, a business unit within Sasol Wax, manufactures and
supplies innovative and unique products based on Fischer-Tropsch hydrocarbons
as well as paraffin and microcrystalline waxes to polymer producers and
converters in the moulding, extrusion, compounding and thermoforming industries.
The Fischer-Tropsch products marketed into the polymer industry are crystalline linear, unsaturated hydrocarbons, or derivatives thereof, which are highly compatible with polyolefins and which can be used as external lubricants in polymers such as PVC.
The paraffin and microcrystalline waxes are low softening-temperature petroleum based waxes. The branched-chain Microcrystalline waxes are particularly effective in PVC systems.
The processing of rigid PVC requires conditions of high shear, temperature and pressure. Under such conditions, the inherent thermal instability of PVC leads to the degradation of the polymer via a mechanism of chain scission i.e. HCl gas formation. Wax based lubricants are therefore required to reduce/control shear conditions and promote flow whilst at the same time control friction and ultimately the fusion properties of the formulation.
By virtue of their highly crystalline structure and linearity, the Sasolwax range of PVC external lubricants have been proven in practice to be extremely efficient when correctly formulated with internal lubricants hence allowing optimal processing and physical properties to be achieved.
EnHance is a highly crystalline Fischer-Tropsch hydrocarbon designed to improve the processability of polyolefins during injection moulding, extrusion, compounding & extrusion blow moulding. Fischer-Tropsch hydrocarbons are highly compatible with polyolefins and at the recommended loadings are dissolved in the polymer matrix. EnHance essentially functions by the mechanism of flow improvement thereby affording the converter the opportunity to improve productivity, efficiency & quality through machine optimization. The AdSperse range of Fischer-Tropsch hydrocarbons has been developed specifically for use as dispersing aids in the manufacture of polyolefin masterbatches and colour concentrates. Fischer-Tropsch hydrocarbons are highly compatible with polyolefins.
Function of Dispersing Aids in Colour Masterbatches
Dispersion involves the breaking up of pigment agglomerates into primary particles/crystals by shear forces. Pigments only develop their full colour potential when the agglomerate form, in which they are supplied, is broken down into a more uniform state consisting of primary particles/crystals. Dispersing aids are used to wet the pigments, to penetrate the small hollows between agglomerated particles and to facilitate the shear-related breakdown of the solid, hard agglomerates. Even after breaking down the agglomerate, the attractive forces between the primary particles/crystals may lead to reagglomeration. Dispersing agents are also used to stabilise the dispersed pigment particles to prevent reagglomeration in the polymer melt.