Shear processing thermoplastics in the presence of ultrasonic vibration
AssigneeThe B. F. Goodrich Company
InventorsBiing-Lin Lee, Cameron Cranston
Life of this patent
Estimating the term…
Abstract
Various processing advantages are gained when ultrasonic vibration is applied to a thermoplastic processing apparatus such as an extruder or an injection molding device. Such advantages include improved flow rate, reduced processing pressure, and consequently reduced processing temperature to mold or extrude the melted thermoplastic. The ultrasonic vibration is desirably applied to the die of the processing apparatus and in a direction longitudinal to the flow of the thermoplastic. Suitable thermoplastics include polystyrene and polyolefins.
Claims4
A process for improving the processability of a shear thinning thermoplastic melt, comprising the steps of:
- melting the shear thinning thermoplastic in a shear processing apparatus containing a die, said shear thinning thermoplastic being a styrenic type polymer or a polyolefin, said polyolefin made from monomers having from 2 to 6 carbon atoms, said apparatus being an injection molding apparatus or extrusion apparatus;
- applying ultrasonic vibration to said die at a frequency of 10,000 to 40,000 hertz at a substantially longitudinal flow angle of about 15 degrees or less to said shear processing apparatus whereby the shear processability of said thermoplastic is improved;
- and
- injection molding or extruding said thermoplastic at a reduced viscosity and temperature.
Dependencies are inferred from the claim text.