METHOD AND SYSTEM FOR CLEANING AND UPGRADING POST-CONSUMER AND/OR POST-INDUSTRIAL POLYVINYLBUTYRAL

A method and a PVB cleaning and/or upgrading system for cleaning and upgrading post-consumer and/or post-industrial polyvinylbutyral (PVB). The system comprises an extraction station for extraction with liquid or supercritical carbon dioxide. The extraction station comprises a scalable container (13) with means for introducing pressurized liquid carbon dioxide into the container and means (4) for stirring PVB material. The station further comprises transfer means for transferring the pressurized liquid carbon dioxide containing extracted plasticizer and/or contaminants from the container to a distillation unit (18). The distillation unit separates extracted plasticizer and/or contaminants from the carbon dioxide, by evaporation of the liquidified CO2. The system further comprises pressurizing means (21), such as a compressor, for pressurizing and liquidifying of the CO2 evaporated in the distillation unit (18). The recovered CO2 is liquidized and pressurized CO2 to the scalable container (13), preferably via a CO2 storage (15). The PVB material is preferably initially subjected to one or more alkaline washing steps, preferably prior to the extraction with CO2. The system and method effectively removes contaminants and/or additives from the PVB and eliminates the use of organic solvents during the extraction step(s).