University of Connecticut

John E Dresty, Jr

Antonio J Aldykiewicz, Jr

James M Fenton

Jung-Chou Lin

Richard Bodensteiner

Chunzhi He

Ramakrishnan Venkataraman

A process for the delacquering and detinning of a metal substrate is presented comprising the fully electrochemical removal of both an outer polymeric coating and an inner tin coating from a metal substrate. The disclosed method provides a clean metal substrate, and results in wastes which are easily disposed of with minimal cost and minimal environmental impact. In one embodiment, the present invention comprises a one-stage process for removing an outer polymeric coating and an inner tin coating from a metal substrate in a single electrolyte bath through electrolytic removal of both the polymeric and tin layers from the metal substrate. An electrically conductive container having the electrolyte bath therein acts as an anode in the process, and the removed tin is plated out on the cathode. In another embodiment, the present invention comprises a two-stage process for removing an outer polymeric coating and an inner tin coating from a metal substrate. The first stage comprises removal of the polymeric coating in a first electrolyte bath through application of a cathodic current to a first electrically conductive container, e.g. tank, drum, or the like. The polymeric and tin coated metal substrate that is immersed in the first electrolyte bath is cathodically protected provided the coated metal substrate is in contact with the first electrically conductive container. The second stage comprises removal of the tin coating via application of moderate anodic currents to a second electrically conductive container, e.g. tank, drum, or the like. Such current results in the selective removal of tin from the substrate metal. The second electrically conductive container and the tin cans act as an anode in the process, and the removed tin is plated out on the cathode.

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South Glastonbury, CT, United States of America

John E Dresty, Jr