The rapid growth in PET bottle consumption, improvements in collection systems, and regulatory changes in Europe are providing new opportunities and challenges for the rapidly developing PET recycling industry. Many products are using recycled materials instead of virgin materials, creating economic and processing technology significance. These include common fibers, thermoforming sheets, nonwoven fibers, packaging tapes, and even masterbatches and bottles. Each of these processes requires specific performance characteristics from the recycled PET material, nearly matching those of virgin material. In addition to molecular weight (commonly referred to as inherent viscosity), foreign particles or contaminants in the melt (such as paper, sand, rubber, PP, and PVC from other plastics) can affect product quality.
High-quality standards must be present in the so-called "bottle-to-bottle" recycling process. In this case, the process is actually viable and economically feasible only when the source of the bottles being utilized is identified and controlled, such as the recovered stockpiled bottles.
If the bottles are sourced from domestic plastic waste, there's a risk of unknown contaminants. Moreover, it will require highly complex sorting and cleaning factories, which increases the cost of flake material. Currently, the collection, packaging, sorting, grinding, cleaning, drying, extrusion, filtration, chopping, and solid-state polymerization processes for PET flake material all create possibilities for efficiency improvements and cost savings. An important trend is to reduce production costs by directly processing cleaned and dried flake material into the above products, thereby eliminating the intermediate step of extruding PET flake material into granules or sheets.
Directly processing PET bottle flakes into the above product makes the production process susceptible to interference. Filtration is particularly crucial. The filtration system must be capable of handling continuously varying pollution loads, must operate automatically, effectively utilize the filtration medium, and of course, it must maintain a high level of process stability in its operation.
