“Paper must be recycled!” Sustainability is increasingly becoming a focal point where paper and packaging are concerned. The process of recycling paper is unclear to many people. What actually happens to hot melt adhesives, staples and the like during recycling?
Let’s look at this subject in detail
Three steps to environmental friendliness
The process of recycling paper is called “repulping”. This is done by mechanical dispersion. Dispersion here stands for dispersion, spreading and fine distribution. The recycling paper fibres are separated, cleansed and foreign particles separated out. Obtaining the fibre raw materials and producing new, recycled paper from these raw materials are two different processes: Our article is mainly about the extraction and processing of the raw materials. Pulp is to be produced from the raw materials. New paper is produced from pulp.
The dispersed paper fibres are screened for foreign substances. These can be remnants of plastic or metal particles. The remnants are separated from the paper pulp (pulp) in a filter process. In addition, hot melt residues must also be removed. The recyclability depends not only on the composition of the adhesive, but also on the amount applied, the form and the layer thickness.
The “European Paper Recycling Council” (EPRC) initiative, founded in 2000, developed a scorecard to assess the removability of hot melt residues in the recycling process. Accordingly, the following requirements should be placed on the adhesive application in order to be considered recyclable:
- Layer thickness = min. 120 µm
- Softening point (Ring & Ball) = min. 68°C
- Adhesive surface = min. 2.56 mm² (1.6 x 1.6mm)
In the case of surfaces that are smaller than the specified 2.56 mm², the residues of hot melt adhesive may, under certain circumstances, not be removed properly. Such adhesive surfaces occur primarily with certain types of application, such as so-called “stitching”. Here, the smallest dots are placed one behind the other. Due to the smaller hot melt adhesive area, packaging with this type of application cannot be recycled well. The separation of foreign substances is essential in the conversion of pulp to recycled paper.
Less is more?
In order to keep packaging or paper that has been glued with hot melt adhesive recyclable, it is necessary to comply with the guidelines of the EPRC. If these guidelines are adhered to, packaging can be recycled well – regardless of the type of hot melt adhesive. The saying “less is more” does not apply in this case: a smaller amount is not necessarily more environmentally friendly, but complicates the recycling process. The recycling process is vital, because repulping paper can save valuable resources.
We hope we were able to introduce topics in this newsletter that were of interest to you.