A method to increase production rate of a continuous mixer or extruder

Abstract

Compounding or extrusion rates can be increased by splitting the polymer solid feed. Melting of additional solid polymer is significantly assisted by excess enthalpy from incoming melt from a primary mixing stage. Depending on resin rheology and melting characteristics, rate increases were achieved of from up to about 55 to about 100% rate increase over the use of a single feed at the same rotor speed. The net result is a decrease in the overall SEI (specific energy input to the polymer) and thus melt temperatures.

Description

technical field [0001] The present invention relates to processing with continuous mixers or extruders, and more particularly to increasing the production rate of such continuous mixers or extruders. Background technique [0002] The throughput of extrusion or compounding lines is often limited by the capacity of the extruder or continuous mixer. Solid fed continuous mixers and extruders are usually run at partial capacity and rarely up to the volumetric melt pumping capacity of the screw. Production rates are usually limited by machine power, solids feed related issues, product quality, or a combination thereof (assuming auxiliary equipment is adequate). For example, the throughput of resins with high melt viscosity is typically limited by machine power. In contrast, the productivity of resins with low melt viscosity is typically limited by issues related to solids transport. In some cases, such as in reactive extrusion and compounding, product quality can also limit pro...

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Problems solved by technology

For this reason, temperature control is difficult to achieve once the polymer is melted

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