Methods for producing polyester film and polyester sheets

Abstract

The invention proposes methods for producing heat-shrinkable polyester films, wherein the heat-shrinkable polyester film is made from components containing recycled material. These methods include: (a) heating a mixture of terephthalic acid (TPA) or dimethyl terephthalate (DMT), ethylene glycol (EG), a modifying component, and optionally, recycled material to undergo esterification to produce an esterified product; (b) heating the esterified product in the presence of a catalyst, a heat stabilizer, and optionally, recycled material to undergo polymerization to produce a polyester product; (c) granulating the polyester product to produce a polyester resin composition; (d) extruding the polyester resin composition to form sheets, wherein the extrusion takes place at a temperature of approximately 180°C to approximately 280°C; and (e) introduce the sheet into a film-forming process to produce a heat-shrink polyester film, in which recycled material is added at step (a), step (b) or both steps (a) and (b).

Images