Ecolabels for printed products require reliable test methods

Paper is sustainable. It comes from renewable resources and can be fully recycled to products of the same value. The paper from today’s news will be back with more news next week.

This only works as long as the printed product remains recyclable – as long as printing inks can be removed during the paper recycling process. Problems can occur from crosslinked inks (liquid toner from HP Indigo, UV cured inks and varnishes). But also many mineral-oil free inks are a source of dirt specks: if the oils used polymerise during oxidative drying and thus are difficult to be removed from the fibres (e. g. soybean oil).

A valid assessment can be made using a test according to INGEDE Method 11. This test is proven for decades and has been optimised regularly. INGEDE Method 11 has become the basis of the evaluation according to the deinkability scores of the European Paper Recycling Council (EPRC) used for many ecolabels: for the Blue Angel for Printed Products (RAL-UZ 195 in Germany), the Austrian Ecolabel for Printed Products, the Nordic Swan and the European Ecolabel.

Find all INGEDE Methods here.

FAQ: Frequently asked questions
about paper recycling and deinking

Put them into the trash. They contain chemicals that shall not go into recycled paper.

The deinking process is a dip for mineral oils. They are being removed in the flotation as they are hydrophobic. The migration issue is more relevant in packaging materials which are produced without deinking.

What happens with the foam? It contains not only ink but mainly fibres. Most of the deinking residue is therefore mechanically dewatered and burnt in the mills’ power plants for energy generation.

Due to the calcium carbonate and kaolin content (fillers and coating pigments), deinking residues can be readily utilised in the manufacture of cement or bricks. The kaolin is aluminum oxide and improves the stoichiometry in the cement production if a local clay deposit lacks aluminum – there has to be a certain ratio of calcium, silica, and aluminum.

The fibres and fines contained are desirable as porosification agents in brick production – when burning the bricks, the fibres leave micropores that increase mechanical stability and insulation properties of the brick. The incineration ash can also be disposed of in this way.

Yes and no. In principal, the fibres are welcome. But they can contribute a lot of unwanted substances, mainly adhesives. The plastic window is no issue as it can be screened off. But the adhesives are difficult to remove – and there can be a lot of adhesives: to glue in the window, from stamps or address labels, and the self-adhesive seal. Furthermore, many envelopes have a light blue or grey imprint, printed with flexo inks that are not removable.

Yes, the result of a deinking test can differ depending on the paper, mainly depending on whether it is coated or not.

But there is no general rule. In many cases, a coating on the surface keeps the ink from direct contact with the fibres. In the case of oxidative drying as in vegetable oil-based inks, the inks cannot cling to the fibres and thus lead to dirt specks. This is why we generally see much more dirt specks with mineral oil-free inks on uncoated paper compared to coated paper.

But there are some situations (also with UV inks that do not stick to the fibres) where the rough surface of an uncoated paper can support the fragmentation of an ink layer and lead to smaller particles that can be removed more easily, while on coated paper this ink might form a homogeneous layer that is less prone to break, leading to larger fragments.

As a result, a deinkability test result is not transferrable in between paper qualities, for an ecolabel a result is necessary on both coated and uncoated paper if a customer wishes to print on both and use the ecolabel for both.

So depending on which paper quality your customers print, use the respective paper for meaningful results.

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