Until a few decades ago a "plastic" object, or a clothing made of synthetic fiber, communicated the feeling of a mass-produced product, certainly functional, but not always synonymous of high quality. Today, the technological evolution of plastic polymers and their technical and aesthetic characteristics has reached levels that were unthinkable until some time ago.
The era of plastics began with the processing of Bakelite and celluloid. However, the plastics market has evolved rapidly to meet the needs of an increasingly demanding customer base.
The plastic material should be properly heated and dehumidified for a correct processing and to improve its aesthetic and mechanical strength properties. For this purpose, in the early 1970s, a container with a truncated-conical shape was created for the dehumidification treatment process. The impacts of the dehumidification process on the quality of the final products have been underrated for long by a fast-running market that lacked the technical expertise to analyse them.
Moretto guessed that dehumidification was a key factor in achieving a stable moulding and extrusion process, one that could guarantee performance under control and in line with the required parameters. It was therefore necessary to examine the behaviour inside the hopper to significantly improve system performance.
Extensive studies began about 30 years ago, and through software for "discrete element" analysis, introduced in 2007, a series of experiments were carried out to evaluate granule by granule the path through the traditional hopper. The analysis showed that with these hoppers, it was not possible to guarantee the release of properly dehumidified material, as it could not be ensured that all granules met the required residence times.
