As recycling has become increasingly important, the potential for recycling a wide variety of plastic waste streams is being carefully assessed. Key factors in this evaluation include the expected annual volume, potential contamination, and material composition of the waste streams. LDPE/LLDPE films, in particular, benefit from established collection systems in many European countries, which have been in place for years to supply material for recycling. With growing market demand for recycled content across various applications, one of the challenges is producing clear shrink, stretch, or blown films that retain their properties while incorporating recycled material.

To address this challenge, new recycling capacities have been built in Europe and globally, or existing plants have been retrofitted with enhanced sorting, washing, and melt filtration systems to provide high-quality polyethylene (rPE) streams for recycling. Despite these advancements, even LDPE/LLDPE material that has undergone extensive mechanical processing can be difficult to convert into new film on traditional production lines. This difficulty has led to a collaboration between Colines, ExxonMobil Signature Polymers, and Gneuss to develop a viable film production process that not only incorporates recycled content but also offers potential cost savings.

A key issue in this process is the presence of gels and black dots, which can disrupt film production. However, with the appropriate materials from ExxonMobil Signature Polymers and a pressure-constant screen changer from Gneuss, these disruptive factors can be minimized on Colines' highly flexible cast film line. ExxonMobil Signature Polymers has conducted trials using Post-Consumer Recycled (PCR) material derived from stretch film, combined with Exceed Tough m 3812 high-performance polyethylene, and observed a reduction in the size of larger polymer gels. According to Bart Lauwers, Principal Extrusion Customer & Application Development at ExxonMobil Technology Group, “With most commercial PCR grades available in Europe today, extrusion lines often cannot run continuously. Continuous filtration can extend extrusion line operation by removing a significant proportion of the impurities, although not all gels.”

Despite these challenges, the project has successfully demonstrated process consistency and film quality. Tests revealed the ability to consistently produce film incorporating 30% PCR content, with a consistency of 180-200% without interrupting the line, except for routine maintenance unrelated to recyclate use. Central to the success of this process is the Gneuss RSFgenius self-cleaning screen changer, a fully automatic filtration system that renews the screen surface without causing pressure fluctuations. This system is adaptable to different materials, with screen finenesses ranging from 30 to 75 microns, even during full operation.

Colines, based in Novara, Italy, is renowned for its flexible film production lines, and has integrated Gneuss screen changers into its systems. The collaboration between Colines, Gneuss, and ExxonMobil Signature Polymers has already led to the establishment of several large-scale production lines dedicated to incorporating recycled content. Looking ahead, the project partners plan to invite industry professionals to Novara in early 2025 for demonstrations. A Colines line, equipped with the RSFgenius 150, will showcase its ability to produce films with thicknesses of up to 10 microns without quality fluctuations, with expertise from ExxonMobil Signature Polymers available for material and additive selection.