Chemical-mechanical stripping of paint from plastic components

The invention relates to a process for removing paint from used parts or reject parts, in particular made from polycarbonate (PC) or a polycarbonate blend, preferably with polybutylene terephthalate (PBT/PC), in order to recycle the plastic. In this process, the plastic parts are first mechanically...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: LOEHR, KARSTEN, MELCHIORRE, MICHELE, KETTEMANN, BERND-UWE, ZUERN, JOERG
Format: Patent
Sprache:eng ; fre ; ger
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Beschreibung
Zusammenfassung:The invention relates to a process for removing paint from used parts or reject parts, in particular made from polycarbonate (PC) or a polycarbonate blend, preferably with polybutylene terephthalate (PBT/PC), in order to recycle the plastic. In this process, the plastic parts are first mechanically comminuted to a pourable part size and then circulated in bulk together with anhydrous alkalinised diethylene glycol or propylene glycol with mutual abrasion of the plastic chips at elevated temperature (at least 50 DEG C, preferably at from 80 to 100 DEG C) until all the paint has been removed. The stripped plastic chips are then separated from the paint remover, rinsed and subsequently dried. The amount of glycol added corresponds to from 1 to 10% by volume of the volume of bulk material to be treated, in such a way that the circulated parts are merely wetted by the glycol, but paint remover from a larger stock is constantly circulated through the treatment space of the bulk material. The circulation of the bulk part is preferably carried out in a sealable free-fall or forced mixer or in a rotary mixer. During the abrasive circulation, abrasive particles whose specific density approximately corresponds to the specific density of the plastic parts are preferably added to the plastic parts.