Enabling circularity! TEGO® Res 1100 ensures faster and better deinking of plastic packaging waste – leading to high recyclate quality

Circular economy for plastics is not only a buzz word in the industry. With the packaging and packaging waste directive becoming effective in 2030 in the EU, the demand for recyclability will further grow.

A big hinderance for mechanical recycling of printed flexible packaging material are remaining unwanted residues from printing inks negatively impacting the recyclate quality and therefore limiting potential secondary uses.

Therefore, full removal of printing inks and other coatings from packaging waste is key  to generate high quality recyclates. Only then true recycling – in contrast to downcycling – becomes possible.

Figure 1: Idealized recycling process

Analyzing the processes along the packaging life cycle, it was possible to identify a new approach that would avoid changing the overall recycling process – but just require a modification of the formulation of the solventborne packaging inks.

The addition of a suitable cobinder would ideally optimize the deinking result.

Evonik Coating Additives has developed a polymer of designed solubility, easy to integrate into ink formulations, easy to implement in a recycling facility and easy to monitor in the process: TEGO® Res 1100.

TEGO® Res 1100 is a methacrylate co-polymer with designed solubility to be used in the formulation of typical solvent based inks. It is highly compatible with various ink binders and solvents like alcohols and esters. The usage of TEGO® Res 1100 maintains the properties of modern high performance inks.

Figure 2: Comparative Deinking test results of a PU based ink according to EVONIK deinking method showing the improvement of deinking speed and recyclates quality.

For initial testing in our Evonik labs, simple caustic soda was chosen to deink at higher pH - without the addition of additional surfactants. This approach would avoid possible side-effects and allow easy process control for the recycler.

However, for lab scale determination of deinking properties, also DIN Spec 19496 (using additional surfactant) was used to show the effectiveness of TEGO® Res 1100 when it comes to deinking.

The effectiveness of TEGO® Res 1100 could be proven with both test methods.

Figure 3: Deinking time of NC / PU packaging ink on BoPP

Depending on the method, deinking speed could be accelerated up to 9 times for conventional Nitrocellulose based inks. For polyurethane based inks we could see that TEGO® Res 1100 allows deinking, which otherwise is not even possible without the use of surfactants in the deinking solution.

TEGO® Res was used in different ink formulations representing different commercially available inks. The most important properties have been checked thoroughly for any negative influence of TEGO® Res 1100.

In Nitrocellulose based inks neither adhesion, nor heat seal resistance, viscosity or wet crinkle resistance showed any sign of being deteriorated by TEGO® Res 1100.

In PU inks a very moderate improvement of adhesion could be found by the additional of TEGO® Res 1100 whilst maintaining all other beneficial properties.

TEGO® Res 1100 enables deinking in easy and energy efficient processes without compromising ink performance lowering the barriers for a true circular plastics economy.