Extrusion has been known as an industrial process for centuries. It is the forcing of a malleable material through a shaping orifice or die, originally by mechanical and later by hydraulic means. These processes were limited to unit production, i.e., one extruded form was made in each actuating stroke. These early rubber extruder screws had low length to diameter (L/D) ratios, as low as 4 to 1 in some cases. Perhaps 60 years after its use in the rubber industry, screw extrusion technology was employed for thermoplastics, initially for materials such as cellulosics and polyvinyl chloride. With the later development of nylon, screw profiles required a transition region to accommodate the rapid shift from solid to melt typical of semi-crystalline polymers, so that such screws had three distinct zones.
Momentive Performance Materials Inc., the world's largest BN manufacturer, is launching new BN-based formulations for creating thermally conductive and electrically insulating plastics at a potentially lower cost than materials already in the market. These hybrid fillers are being marketed under the CoolFX trade name. These new CoolFX hybrid filler formulations can be cost effective solutions for thermal management applications because they achieve high thermal conductivities at lower BN loadings. They are now available for sampling as single powders, offering more consistent feeding in compounding than traditional BN powder.