Additives and fillers are organic or inorganic compounds that Bausano customers can introduce into plastic to change the properties of the specific plastic for extrusion. While most plastics in their original form are impact resistant and long-lasting, they are often brittle, hard, combustible, or too heavy for the intended use. Adding additives or fillers can transform the plastic so it meets the intended use without sacrificing the qualities that made it attractive in the first place.
In the processing of plastic, Bausano makes a distinction between additives that have an influence on the process ability of the plastic and additives that have an influence on the product properties.
Fillers in polymer Extrusion
Fillers are added to polymers by customers before putting it in a Bausano extruder to accomplish many different property changes and improvements. They can alter physical properties, reduce costs, trim weight, change the electrical conductivity, and enhance thermal properties, just to name a few. In almost every case they also influence processing behavior during extrusion.
The polymer can be mixed with up to 85% of fillers such as chalk or talcum.
The addition of fillers can significantly change the processing properties of a polymer. Refer to general melting-rate calculations for viscous dissipation in Bausano single-screw extruders (shear melting) it's important. Viscous dissipation is increased with increasing viscosity, density, and thermal conductivity, and by decreasing specific heat.
Adding fillers to the polymer mix affects all these parameters. The generation of heat in the polymer itself depends on its thermal properties, viscosity, and the conductive heat transfer to or from the extruder. By adding most fillers, the amount of energy required for viscous dissipation is greatly reduced in relation to the mass output.
Polymers are poor conductors of heat compared with mineral or glass fillers. Moreover, polymers require more energy to raise their temperature (specific heat). Additionally, most fillers have a significantly greater density than the common polymers, giving them more “thermal bulk.” Finally, addition of fillers usually increases the compound’s viscosity as compared with the neat polymer. You can use the reference point from processing unfilled polymer to determine whether you can run filled resin on your current system.
Often, minerals such as calcium carbonate, silica, clay, kaolin and carbon are added as fillers to polymers. While most people think these are simply used to add bulk and lower cost, many of these mineral fillers make them easier to mold and shape while ensuring the stability of the compounds. For plastics that require heat-resistance, mineral fillers can increase heat-deflection and reduce thermal expansion.