Europe – The European Recovered Paper Council has released a document, which provides an assessment of the removability of adhesive applications of a printed paper product as one aspect of its recyclability.
The assessment scheme deals with the fragmentation of adhesive applications and their removability through a laboratory screening process. It is applicable to all kinds of printed paper products containing any adhesive applications and serves as an evaluation for potential sticky problems at the paper machine and quality defects in the produced paper or board.
ERPC – which connects various parties in the paper manufacturing and recycling chain- says the sufficient removal of adhesive applications is one of the challenges for the paper manufacturers using recovered paper.
In the recovered paper treatment process, adhesive applications disintegrate during pulping to “stickies”. Stickies is a broad term for all tacky components in recovered paper pulp.
Depending on their size and their behaviour they are called macrostickies, microstickies or potential secondary stickies. Mechanical screening with slotted screens is the most efficient tool for sticky removal. High removal efficiency can only be achieved if adhesive applications disintegrate into particles of large size. The smaller the particles are, the lower their removal efficiency is. In addition, they can re-agglomerate later in the papermaking process and thus form secondary stickies which lead to major problems in paper production and/or converting processes.
In this regard, the removability depends not only on the composition of the adhesive but also on the type of application, such as the shape of the application and the thickness of the layer. The larger and thicker the layer of a given adhesive, the less disintegration into small particles occurs.
All these characteristics have been taken into account in the resulting ‘Scorecard for the Removability of Adhesive Applications’ available on the ERPC website.
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