Test washing procedures were developed to determine whether on-pack adhesive and label combinations are fully compatible with the post-consumer HDPE or PP recycling stream. They are destined for the label and adhesive industry as well as the recognized Certification Bodies which perform recyclability assessments of labeled packaging.
These standard procedures were developed at a laboratory scale to allow companies to easily and quickly check the wash-off compatibility of their labels with recycling. The documents describe the steps that must be followed to carry out the analysis, as well as the assessment criteria to evaluate the behavior during washing.
As reported in the HDPE & PP Design for Recycling Guidelines, any label and adhesive combination must be water soluble or water releasable at 40°C to get separated from the packaging during the recycling process. Additionally, paper labels must ensure no loss of fibers during the washing step to avoid wash water contamination and recyclate damaging.
The Washing Quick Test Procedures were developed by the RecyClass HDPE and PP Technical Committees and, in particular, the adhesive and label manufacturers including Henkel, UPM Raflatac and Avery Dennison, that carried out internal testing to validate their feasibility.
In the case of the non-removable adhesives in combination with film labels, they can be tested by RecyClass following a complete assessment according to the RecyClass Recyclability Evaluation Protocols, to identify their impact on the quality of recycled HDPE & PP.
Every component of plastic packaging must be considered when evaluating its recyclability. Labels and adhesives are just one of the examples. Making sure that they are compatible with recycling technologies is indispensable in driving high-quality recycling. By ensuring compatibility with the recycling process the quality of the recycled material increases and so does their potential for being used in high-end applications.
Published in the June 2021 Edition
