Herma self-adhesive division marks a breakthrough for wash off

Packaging Solutions

Herma self-adhesive materials division has achieved another breakthrough in the recycling of plastic packaging: it is likely to be the first supplier to hold certificates confirming that seven PP and PE based self-adhesive materials can be completely released from rigid PP packaging even during energy efficient cold washing – an important prerequisite for achieving the purest possible recycled material.

The certification is based on the CHI Recyclability Standard developed by the cyclos-HTP Institute, a methodology for assessing the recyclability of packaging that is aligned with the requirements of the PPWR.

The tests were carried out for the rigid PP recycling stream, taking into account PPWR Category 12. Wash off solutions for the recycling of PP packaging are considered particularly challenging.

‘Unlike in the long established PET recycling process, PP packaging and PP or PE label film – including the adhesive – have an almost identical material density. Separation is therefore carried out by air classification after the label material has been removed. Until now, there have been no certified solutions for this. So far, the focus has not been on the label, which carries the printing ink. However, this is now changing drastically as a result of the PPWR,’ explained Dr Stefan Kissling, head of adhesive coating and special coatings at Herma. ‘The fact that labels can now demonstrably be separated from the actual packaging material during a cold wash is a major step forward.’

As the label helps to remove the problematic printing ink from the recycling process in this way, purer recycled material can be produced.

PP (polypropylene) packaging is widely used, for example for foodstuffs such as yoghurt pots and delicatessen containers, for cosmetics and for logistics applications. The certified Herma range of six PP films covers all standard applications. The range includes Hermatherm PP el (grade 827) and PP plus (829), Herma PP white super tc (881) and PP white light (884), as well as Herma PP 50 transparent super tc (886) and Herma PP white 40 (892). A key factor in the successful certification is the multi-layer, permanent pressure sensitive adhesive 72Hpw developed by the company, which once again demonstrates its performance in terms of wash-off resistance in tests carried out by the independent institute cyclos-HTP. For applications requiring particularly flexible labels, it has also obtained a certificate for the PE film Herma PE white (850) within the same PPWR category. In this case, the multi-layer pressure sensitive adhesive 62Xpc – developed specifically for films – is used.

‘Being arguably the first manufacturer to present a certificate in accordance with PPWR Category 12 for the cold wash process of PP or PE films on rigid PP can be described as a genuine breakthrough,’ explained Dr Stefan Kissling. ‘We are thereby solving a key problem in the PP material flow. Brand owners, packaging service providers and label printers now have a solution to comply with the EU Packaging Regulation (PPWR).’