Infrared drying can significantly improve the performance of a twin-screw extruder because it reduces the degradation of IV value and significantly improves the stability of the entire process.
For safe storage, the moisture content (MC) in the normally harvested corn is higher than the required level of 12% to 14% wet basis (w.b.). In order to reduce the MC to a safe storage level, it is necessary to dry the corn. There are several ways to dry corn. Natural air drying in the tank occurs in a dry area from 1 to 2 feet thick that slowly moves up through the bin.
Drying and Crystallizing before Injection molding processing. It must be dried before molding. PET is very sensitive to hydrolysis. The conventional air heating-dryer are 120-165 C (248-329 F) for 4 hours. The moisture content should be less than 0.02%.
The extruder with Double vacuum station enough to dry the flakes in the process, then no need pre-drying?
In recent years, there are multi-screw extruder system have been established in the market as an alternative to Single – screw extruders with a pre-drying system. (Here we call multi-screw extrudering system including Twin-screw extruders, Planetary roller extruders etc.)
Virgin PLA resin, is crystallized and dried to 400-ppm moisture level prior to leaving the production plant. PLA picks up ambient moisture very rapidly, it can absorb around 2000 ppm moisture at open room condition and most of the problems experienced on PLA arise from inadequate drying. PLA is required to be properly dried before processing.