The Brighter Future for PET Recycling

From Petcore's PETPlanet Column - Vols 1&2 2010
www.petpla.net
Post-consumer recycling of PET containers is gaining momentum. As the industry looks increasingly towards the opportunities for a cradle-to-cradle system, where containers are recycled back into new PET containers rather into other PET products, we need to consider the long-term effects of multiple recycles on the quality of final container aesthetics.
 
Increasing volumes of containers entering the recycle stream already contain significant proportions of recycled material. The result of this current “success” in recycling is, however, likely to have a negative impact on the long term aesthetic quality of PET containers as the quality of resin potentially deteriorates with each recycle trip.

 
Consider also, that a large volume of preform production contains faster reheat resin (for example for carbonated soft drinks), which can further compromise container aesthetics.
 
Taking a common scenario, the first time a container is recycled it could typically contain up to 30% recyclate. Through multi-trip processing a proportion of the recyclate will have gone through one or more process histories.  Through multiple cycles it can become increasingly difficult to maintain good aesthetics of recycled containers.
 
In order to withstand the rigours of multi-trip processing, PET resin will need to become more robust so that when it re-enters the recycling stream at each stage it is as “clean” as it possibly can be.
 
Research into improving PET process capability through the recycling stream has developed a number of potential solutions to this problem.  By improving the capability of reheat technology in PET preform processing, researchers at a colorant and additive dispersion specialist (a Petcore member) believe this issue can be overcome.
 
Although reheat capability can be taken to extremes to create perfectly clear preforms, a balance needs to be struck between achieving an economically viable reheat process and optimised container aesthetics.
 
This new reheat technology incorporates a high performance IR absorption component that has been shown to achieve greater reheat capability compared to currently available technologies whilst at the same time demonstrating a masking effect on any potential resin yellowing occurring after multi-processing. The technology has by its very nature an inherent blue toning quality which results in a clear, bright container.  This counteracts any yellowing that can cause a hazy effect on the final container and ultimately yields a higher quality recycled material.
 
In studies through five process histories the reheat technology has been shown to maintain 100% of its IR absorption.
 
 
 
In PET container recycling at least, moving towards cradle-to-cradle “reincarnation” now appears to be a step closer to becoming a realistic solution for the future.
 
Many Petcore members are investing in technology development to allow brand owners to package their products in recycled-content containers to give maximum shelf life and attractive aesthetics. Their ultimate aim is to produce PET recyclate of the best possible quality from existing bottle collection. A positive contribution from a sustainable industry.