Reliable production combines rPET traceability with control of material and process parameters. A change of supplier or rPET proportion should be assessed technologically as well as commercially, with attention to the finished packaging.
Control rPET as a material, not just a percentage
Adding recyclate to a formulation should not be based solely on its percentage. Each batch has properties that may affect processing and the finished product.
Suppliers and traceability
The organisation should know the rPET source, certification status, specification, batch number and delivery documents. To verify a recycled-content claim, the material must remain linked to the process and the product.
Moisture and drying
PET is sensitive to moisture during processing. Inadequate drying can accelerate hydrolytic degradation and affect material properties. Drying parameters should be controlled and matched to the feedstock.
Blend consistency
When rPET is mixed with virgin plastic and additives, the proportions should be known and repeatable. A change in rPET content may require adjusted process settings or renewed product evaluation.
The preform
Control weight, dimensions, appearance, colour and the characteristics relevant to subsequent blow moulding. Variation in the preform can affect how material is distributed in the finished bottle.
Blow moulding and wall-thickness distribution
Bottle geometry and blow-moulding settings determine wall-thickness distribution, material orientation and mechanical performance. The effects of rPET should therefore be assessed on the actual packaging, not just on pellets.
Finished-pack quality control
Depending on the application, checks may include weight, thickness, dimensions, colour, load resistance, leak tightness and barrier properties.
A supplier change needs evaluation
A new rPET grade may meet the same commercial specification yet behave differently during processing. Define qualification and testing procedures for significant material changes.
The key conclusion
Stable rPET production requires simultaneous management of material origin, feedstock quality, process parameters and the properties of the finished packaging.