German self-adhesive technology specialist Herma has launched 52W, a new wash-off label adhesive developed especially for PET bottles that satisfies stringent requirements imposed on collection schemes.
The new adhesive ensures that the labels are washed off the bottles without leaving any residue but also that any tackiness, which would allow the labels to stick after washing, is removed. Even with standard PP films, it washes off PET bottles without leaving any residue at 65 degrees Celsius. In addition, its unique formulation ensures reliable separation of labels and PET bottles throughout the recycling process.
The new adhesive has been approved by the Norwegian collection scheme Infinitum and added to the list of recommended adhesives by the Swedish equivalent Returpack. The approval and the recommendation concern the adhesive in combination with the label materials Herma PP white super tc (grade 881) and Herma PP 50 transparent super tc (grade 886).
‘52W enables us to ensure that label particles cannot regain their stickiness during drying and then become attached again to the washed PET flakes. In the context of separation for recycling, this is a key requirement of the Norwegian and Swedish recycling regulations. Therefore, the PET flakes can be separated from the labels, ready for recovery and conversion, using either the sink-float or air classification technique,’ said Dr Ulli Nägele, head of development at Herma.
‘Practical tests have shown a similar behavior with our adhesive 62Rpw, which we unveiled back in 2019. Grade 52W now enables us to comply with the requirement even with a washing temperature as low as 65 degrees Celsius. Often in other countries, a temperature of 80 degrees Celsius is the norm. Our development team was put to the test again, but prior experience in this field enabled us to deliver results quickly,’ added Nägele.
Scandinavian countries rank among the driving forces in PET bottle recycling. In Sweden, for example, around 90 percent of used plastic bottles are already being recycled, and the corresponding figure for Norway is said to be greater than 95 percent.
‘In addition, adhesive labels are traditionally more widely used for PET bottles in Scandinavia. For this reason, absolute process reliability is essential. PET is the only plastic which, even as a post-consumer material, can be converted by appropriate recycling methods into recovered pellets that meet the statutory requirements governing direct food contact.’