As for polymer melts, procedures were proposed to devolatilize them to less than 500 ppm (preferably 150 ppm) of residual volatile material.
As a result of the significant differences between latexes and other polymer systems, the mechanism of devolatilization and the equipment used to devolatilize latexes are often different from those used to devolatilize other polymer systems (98).
25) involves the use of a two-stage screw to first feed and melt the material, then decompress and devolatilize
the melt, and finally recompress and pump the material into the shot reservoir downstream of the check valve prior to injection into the mold.
This "REM" (reactor, exchanger, mixer) device, built by TIM Industrie in France, can devolatilize highly inked or contaminated films or mixed waste.
Sikoplast of Germany showed an unusual use for a strand pelletizing die, situated between two single-screw extruders in a system designed to devolatilize heavily inked films.
A ZSE-27 mm twin screw will devolatilize
and pump the primary melt into a new multi-strand die, while a Micro-18 mm twin-screw feeds the same die and coats the strands with a thin outer layer.
Twin-screws can also gently devolatilize
moisture-laden materials like wood flour.
The HVTSE extruder devolatilizes
and demoisturizes the material as part of the extrusion process.
This process relies on Bandera's patented High Vacuum Twin Screw Extruder (HVTSE), which devolatilizes
and de-moisturizes the material as part of the extrusion process, reportedly saving more than 35% in energy use.
The process pulverizes PET flake to about 300 microns, devolatilizes
the powder under vacuum for 5 hr at 338 F, then compacts the powder into porous pellets using a patented additive (U.
A new two-stage extruder system devolatilizes and extrudes wood-filled compounds in one extrusion pass without needing a dryer or a second extruder.
The system has 34:1 L/D, including both sections, but devolatilizes as effectively as a 42:1 conventional extruder, Coronado says.