Composition and process for recovering coated polyester materials

Abstract

The present invention is directed to a process for separating polyester materials from various coating materials. In general, the process includes the steps of mixing polyester materials which have coatings adhered to the surface with an alkaline composition in a mixer. The alkaline composition contains a solution of a Group I alkaline compound and a Group II alkaline compound. The mixer imparts sufficient energy to the slurry to provide substantially complete, even coating of the polyester containing materials with the alkaline composition and cause separation of the coating materials from the surface of the polyester substrate. The mixture can be dried causing the remaining coating materials to form a dry powder mixed with the polyester substrate. After drying, the coating materials can be substantially removed from the polyester substrate by one or more dry separation techniques. After being subjected to the dry separation techniques, any remaining coating materials can be removed from the polyester substrate by a standard wash or rinse technique. Through the process of the present invention, polyester can be separated and recovered from waste materials such as those containing non-aqueous based silver emulsion coatings found in digitally printed X-ray films and the silver in such films can also be recovered. Through use of dry separation techniques, many environmental concerns and disposal problems encountered due to water treatment requirements of aqueous separation techniques can be alleviated.

Dependencies are inferred from the claim text.