Recovery of polyvinyl butyral from laminated glass avoiding physical and chemical degradation

摘要

Polyvinyl butyral, or comparable polymer sheet, is recycled in this process, in which laminated glass sheets are pre-comminuted by splintering and/or crushing; the adherent glass particles being largely removed. In the new process, the sheets experience impact- and frictional forces from different directions in a grinding medium, until adhesion between the sheets and glass particles is broken down, at the same time pulverising foreign matter present. The mixture is then scrubbed vigorously to remove particles from the sheets, which are then separated and dried. Further size reduction may take place, followed by extrusion of the recovered plastic to a sheet or granulate. Whilst in the molten state, residual impurities are extracted. Wash fluid from the scrubber is separated from the solids, and re-introduced into the process.