Since the early 2000s, the weight of a 0.5 litre bottle has been reduced by half, possibly pushing acceptance limits for most consumers. Technological enhancements have enabled cost-reduction and contributed to positive environmental impact. Many assume that lighter weight only has positive benefits, but a recent study by PTI shows that while these bottles can meet consumer expectations for convenience and price, they might not minimise the carbon footprint.
The study found a wide variation in performance, weight and recyclability in the bottles it examined. It discovered that lighter weight, design and label choices have an impact on post-consumer recovery. The decisions made during the design phase not only have to meet physical performance requirements, but also should not negatively impact current recycling systems.
While weight reduction results in a lower carbon footprint, it was found that ultra-lightweight bottles can negatively impact the effectiveness of post-consumer package waste sorting and recycling systems.
The study showed that many of the samples did not factor in generally-accepted recyclability guidelines during the design process. In some scenarios, the PET package design had strong shelf presence and met the functional requirements. However, the bottle colour, label, glue or ink components had a significant impact on package recyclability.
This study therefore suggests that manufacturers need to consider more than just meeting consumer demands (lightweight, size, shelf-appealing designs, etc.) in order to ensure their PET bottle truly minimises carbon footprint.