How the silicone cartridge enlightened us

How can a relatively small problem provide great insights? The participant members of the silicone cartridge  project can answer this question. They worked together to tackle the problem of the disposed cartridges. The disposal and recycling of the  cartridges that are (nearly) empty are not  straightforward: they end up in the household plastic packaging through a number of ways and this stands in the way of a recycling process that is sustainable for the future.

All links in the chain

With twelve participant parties joining, every company in the supply chain was represented. And this is key to success: in order to improve a process that covers so many links in the chain, results are likely to fail if one link is missing. Once you get all of them around the table (producer, supplier, wholesaler, waste collector, waste sorter, recycler etc.) you can actually start to imagine results at the end of the line.

Contents vs. packaging

The silicone cartridge itself is not the problem, the leftover contents are. Many of the disposed cartridges  still contain bits of glue and they can obstruct the machines. By establishing this, an important conclusion is: not the packaging should determine the way of disposal but its contents.

Despite the increased cooperation on a European level, the disposal of silicone cartridge differs by country. Therefore one of the recommendations is: set up a research on how cartridges  are disposed of in Belgium and in Germany. The results of this research could help develop a uniform model for disposal in Europe.

Symbols & watermark

Home improvement stores in the Netherlands have asked their suppliers to apply a waste symbol on the packaging. This symbol informs the buyer – either professional or DIY – on how to dispose of the cartridges.

Another solution coming out of the project is applying a watermark on the packaging. The watermark would cover the whole surface of the packaging in order for it to be picked up by a scanner, even when it’s only partly visible on the conveyor belt. Using a watermark could not only prove helpful for the silicone cartridge but also for other purposes, like separating food from non food.

A waste symbol is information for the customer, a watermark is information for the waste sorting companies. It wouldn’t even be visible for the customer. Thinking ahead, symbols and watermarks can be used for marketing and logistics purposes, too.


Working together on an improved disposal of silicone cartridges shows us how useful it can be to experiment. Trial and error are essential for innovation. In a project setting where all stakeholders play their part, there’s room for transparency and open communication. Results (whether failure or success) are shared and are there for everyone to see.

The findings coming out of this project go beyond the high tack market. TUSTI, a recycling company, conducted an experiment to see whether it’s possible to remove the leftover bits of glue from the cases (see report). Den Braven (sealant producer) placed, together with its suppliers, a watermark on their cases to participate in a sorting experiment by TOMRA and P&G (see PETCycle project).

Silicone cartridges in a circular economy

The silicone cartridge project is part of the broader ambition to close the loop of plastics. The final report “Silicone cartridges in a Circular Economy” (Dutch) is the result of the chain project at the request of the Chain Agreement Plastics Cycle and the Waste Funds Packaging. The idea of this project was put forward by Michiel Westerhoff (Circulus Berkel) in the steering committee of the Chain Agreement Plastics Cycle and is carried out by Partners for Innovation.

  • More information

– The report with conclusions & recommendations (Dutch)

– The report  “Recycling of sealant tubes”

-Website Kunststofkringloop  (Dutch)

-Website PETcycle project  (English)

  • Project Participants

QCP (Quality Circular Polymers), SUEZ, VWDHZ (Vereniging Winkelketens Doe Het Zelf), Circulus-Berkel, Den Braven Holding B.V., Afvalfonds Verpakkingen, Nedvang, Vereninging Lijmen en Kitten VLK, LCKVA (Learning Centre Kunststof Verpakkingsafval), KIDV (Kennisinstituut Duurzaam Verpakken), TUSTI, Filigrade, Fischbach, Partners for Innovation, Ketenakkoord Kunststofkringloop. ·

  • Contact

Ingeborg Gort