Siegwerk patents deinking primer for flexible packaging recycling

Siegwerk has secured a European patent for primer technology that enables printing inks that are not de-inkable in commercial processes to be removed from plastic substrates during recycling. It is said to be able to apply to complex printed flexible packaging structures.

The company says the new European patent complements its US Patent US12291051B2. The patented technology covers solvent-based and water-based deinking primer technologies, while Siegwerk’s broader deinking portfolio incorporates solutions for UV printing applications. 

Lara Kleines, recycling and polymer expert at Siegwerk, says: “We recognized early that removing printing inks can contribute to improving the quality of recycled plastics. This becomes even more relevant as the value chain needs to deliver significantly more recycled material at the quality required for its next application.” 

“Especially for flexible packaging, there will not be one solution for every structure and recycling stream. Our early investment in deinking solutions and the expertise we have built put us in a strong position to support the industry wherever ink removal becomes an important lever for recyclate quality.” 

Rising demand for high-quality recyclates

Under the Packaging and Packaging Waste Regulation (PPWR), plastic packaging will be required to contain a minimum percentage of post-consumer recycled material from 2030, increasing the demand for clean, high-quality recyclates. 

According to the Circular Economy for Flexible Packaging, around 2.5 million metric tons of flexible packaging derived from post-consumer recyclate will be required by 2030 to meet PPWR recycled-content targets for flexible packaging. 

Siegwerk highlights that effective ink removal can help improve recyclate quality by reducing discoloration, odor, and contamination. 

“For rigid packaging, ink washability and the removal of print and decoration are increasingly reflected in European Design for Recycling criteria. Current European Committee for Standardization’s standardization work from the EN 18120 series considers de-inkability as well as the removability of labels and sleeves when assessing the recycling compatibility of certain rigid packaging structures,” says the company. 

“For flexible packaging, the situation is more complex. Printing inks often cover larger surface areas or are embedded within laminated structures, while adhesives, barrier layers, and multilayer constructions can further complicate sorting, washing, and recycling. This makes effective ink removal particularly important for improving the quality of recovered polymers.” 

Solution for various substrates

Siegwerk recognizes that effective ink removal can enhance recyclate quality and has been developing dedicated deinking solutions for printed plastic packaging for several years. 

One of these solutions is covered by the newly granted European patent (EP4107326). At its core is a functional primer positioned between the plastic substrate and the printing layer. 

During alkaline washing, the primer allows the printing layer to be released and eliminated before the polymer is reprocessed. The protected concept is not limited to simple surface-printed structures. It also focused on constructions in which the ink is located between additional layers, extending its applicability to complex flexible packaging, labels, and shrink sleeves. 

Siegwerk says it has validated the technology across different substrates, ink technologies, and packaging constructions in its internal deinking laboratory, as well as in collaborative research and industry projects. 

This year, Siegwerk announced the availability of Colorwerk FastMatch Cloud, a cloud-based color management solution developed in collaboration with X-Rite Pantone, a color science and technology company. 

Meanwhile, the global provider of printing inks and coatings launched the heat-sealing lacquers portfolio within its Cirkit coatings brand.