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Process for the Delamination of Multilayer Plastic Film

Technology Overview

Laminated materials have many technical advantages, but they present a significant problem when it comes to recycling due to the differences in melting points between the polymeric materials that make them up, thus restraining them from being reprocessed by extrusion. The traditional methods used for delamination are based on selective dissolution, in which each layer is solved using organic solvents. These solvents present environmental and safety problems since they are toxic and flammable. On the other hand, because of the price of the chemicals, these methods are not feasible for most laminated materials.

The technology owner has developed a patent pending procedure for the delamination of multilayer film or laminated plastics. The procedure uses micro-needles in a micro-perforation device, comprising at least a pair of double rollers rotating in opposite directions, to make micro-perforations in crushed laminated plastic material and then introduced into a reactor so that water-based agents can access the interlaminar zone of the laminated plastic material and remove the ink and adhesive.

The method was tested with different types of laminates at laboratory scale: PE/PET, PP/ink/PP, PP/aluminium/PE. The technology owner is keen to collaborate with a company through technology licensing agreement. The company should be responsible for the development of the industrial prototype (500 kg/h with an estimated cost of EUR1.2 mil), the validation of the technology, its installation and its introduction into the market. The technology owner will provide technical assistance in each step. The technology owner would also be interested in establishing technical cooperation agreements to further develop the laboratory-scale prototype, to find new applications or to adapt it to the company’s needs.

Technology Features & Specifications

The proposed technology has the following features:

  • Works with regular flake size of about 3-8 cm length
  • Works effectively for aluminum laminated, non-aluminum laminated packaging and co-extruded multilayers with polyamide
  • Superficial contamination is removed through the process which is a washing procedure
  • Uses water-based agents without hazardous reactants for dissolution of adhesive material (e.g. polyurethane-based adhesives) and ink (e.g. polyurethane- and nitrocellulose-based). The water-based agent is recovered with water after the decantation of the inks and recirculated back into the process, reducing operating cost
  • Average reaction time is 1 h with up to 100% ink removal in 90% of the cases

The procedure consists of the following steps:

  • Conditioning and crushing of the laminated plastic material (optional)
  • Micro-perforation of the laminated plastic material
  • Removal of any ink or adhesive
  • Separation of water from the plastic material in a centrifuge
  • Removing of any ink or adhesive from water in a clarifying centrifuge, by adding flocculants and coagulants before the centrifugation
  • Separation of plastic materials by wet-phase decantation based on the difference in density between the various plastics, through the use of hydrocyclone or any other separation technique available on the market

Potential Applications

This procedure could be useful in the plastic recycling sector since it can be applied to different types of laminates from plastic waste of both industrial or domestic origin.

Customer Benefits

This technology has the following advantages:

  • Reaches an efficient plastic delamination for the vast majority of multilayer plastics, allowing them to be recycled
  • Eliminates printed ink present in the interlayer
  • Simple and easy to implement
  • Environmentally friendly procedure without the use of organic solvents

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