The new Packaging and Packaging Waste Regulation directs that, by 2030, all packaging placed on the European market must be fully reusable or recyclable. That includes the ubiquitous multi-layer aseptic carton packaging used for beverages and food products of all kinds.
Recycling these cartons is challenging. Composed mainly of cardboard fibre (75%), these containers also have thin layers of polyethylene (20%) and aluminium (5%) foil inside to protect the contents from contact with external agents. At the end of life, the cartons are taken to a paper mill, where a pulper separates the paper fibres from the non-paper layers. These are fed back into the recycled paper chain. Until recently, the residual PE and aluminium were simply incinerated. Today, however, in line with the sustainability ambitions of the EU and the new legislation, new applications are being developed for this ‘PolyAl’, as the residual compound is called.
One company that has risen to the challenge is Italy-based extrusion machinery expert Bausano.
The company has developed a solution enabling the LDPE- and aluminium-based post-consumer waste from this packaging to be converted into core tubes for winding reels of cloth, film, paper, and other materials.
Bausano’s E-GO R extruder line consists of a single-screw extruder for E-GO R 60/37 tubes with double degassing and forced loading system, making it ideal for managing the density of the material and ensuring its smooth flow within the machinery. Prior to extrusion, the material undergoes a densification process, which is essential to increase its firmness and transform it into a manageable compound suitable for further processing.
The final output is a robust tube with a smooth external and internal surface feel that offers a cheaper alternative to traditional cardboard or virgin polymer cores.
In developing new solutions such as this, Bausano works closely with its customers to establish exactly what is required. “A rigorous process, which qualifies the company as a reference point for the development of innovative solutions capable of satisfying even the most complex production needs, linked to the recovery of non-conventional materials," said Marco Masiero, extrusion test manager at Bausano.
The company first performs feasibility studies in advance of the project before developing a customised line to fulfil all requirements.
Then, in the lab, the material is analysed using a capillary rheometer to determine its viscosity as a function of the shear rate. Knowing the rheological characterisation of the molten material allows the design of the screw and extrusion head to be optimised. Further testing using a Brabender plastograph provides crucial information for predicting the behaviour of the cast material during all processing steps and making it possible to accurately record values for the mixture's melting speed, rotor torque and energy required for the process.
Data obtained through fluid-dynamic analysis were compared with the rheological characteristics of known materials compatible with extrusion. The comparison showed that the process parameters of the PolyAl processed by the customer were in line with those of materials shown to be easily extruded using Bausano technology.
Finally, verification of the feedback from the laboratory instruments is carried out. During this last phase, the waste polyAl is tested with an MD30 twin-screw counter-rotating laboratory extruder to confirm the suitability of the solution for industrial scale-up in terms of amperage, thrust and head pressure values.
Founded in 1946, Bausano is an international expert specialising in designing and manufacturing custom extrusion lines for processing plastics. Headquartered near Turin, the company has 120 employees, a turnover of more than €25 million and a global presence thanks to production units in Brazil and India and a commercial branch in the United States.