Recycling and reusing ABS plastics in-house

Recycling on your own doorstep sounds almost too good to be true. But it is possible, as the Hansgrohe Group in Offenburg shows. The special highlight is that Hansgrohe, in partnership with ImpulsTec GmbH, has succeeded in recycling galvanized plastics. This means that decoated ABS plastics can be recycled directly in the company.

David Zapf, surface technology specialist at Hansgrohe, explains in an interview with K-Mag what the challenges were in developing the technology and what benefits his company can derive from it

How did the partnership between Hansgrohe and ImpulsTec GmbH come about?

David Zapf: The mixers and showers from the Hansgrohe Group, a manufacturer of premium and designer products for bathrooms and kitchens, are manufactured to high quality standards. We focus on the durability of our products, as customers use and clean them many times a day for years. This requires a particularly stable bond between plastic and metal in the production of ABS components, which are finished in an electroplating process.

Despite sophisticated production processes, parts are always rejected in the quality inspection after electroplating, even if the reject rate is only in the single-digit percentage range. However, the large quantities that we produce result in corresponding volume. For this reason, Hansgrohe had been looking for years for ways to return rejects from plastic electroplating back into the production cycle in a meaningful way. Until the start of the project, everything was sold to external partners.

In 2019, I became aware of the technology of the plant manufacturer ImpulsTec through research as part of my master's thesis on "Development and verification of recycling processes for galvanized plastics". This is how the cooperation between Hansgrohe and the specialist for the electro-hydraulic shredding of electroplating waste came about.

Can you tell us more about the newly developed recycling process for chrome-plated plastic components? Which technologies are used?

Zapf: From 2021 to the beginning of 2023, we worked with our partner ImpulsTec to develop a process for decoating electroplated plastic components. ImpulsTec focuses on the development and realization of industrial shock wave shredding systems. The idea was to combine shockwave treatment with pre-shredding and subsequent magnetic separation.

The processed material goes into the third container and is dried there. The individual material particles are then separated from each other using magnetic separation. The majority of the material, 70 to 80 percent, is plastic. In order for high-quality new products to be manufactured from it, it must have a stable purity of at least 99.8 percent. The remaining material fraction is made up of the metals copper, nickel and chromium from the electroplating and is passed on to metal processing companies.

What advantages does this process offer over conventional recycling methods?

Zapf: The quality feature of electroplated ABS parts – the particularly stable bond between plastic and metal – was a particular challenge for the recycling process. As it was not previously possible for us to separate the thin electroplated layer from the ABS while retaining both individual materials, we passed the chrome-plated components on to external recycling partners. This was only a suboptimal solution for us due to the transportation routes involved. The new process developed together with ImpulsTec now allows us to sell the resulting metal fraction (copper and nickel) and return 100 percent of the shredded plastic to the raw material cycle of our production.

How does the new recycling process contribute to Hansgrohe's sustainability strategy and what ecological and economic benefits does it bring?

Zapf: Becoming part of the circular economy is one of the Hansgrohe Group's key areas of action in its sustainability strategy. It is an urgent concern for us to gear our production towards sustainability. By using or recycling products and materials for a long time, we reduce both our use of resources and transportation routes. The new processing plant therefore offers not only ecological but also economic benefits for Hansgrohe. The plant was designed for an annual throughput of 100 tons of chrome-plated plastic. In purely mathematical terms, this amount of recycled ABS can be used to produce one million new hand showers.

What challenges did you meet during the development and implementation of the recycling process and how did you overcome them?

Zapf: Due to the general shortage of materials during the coronavirus pandemic and the increase in component prices, the delivery date was delayed several times. However, we were able to overcome these challenges together with our partner ImpulsTec.

What happens to the separated materials after the recycling process, in particular the highly concentrated metal fraction and the decoated ABS plastic?

Zapf: On the one hand, our new plant supplies a highly concentrated metal fraction, which mainly contains copper and nickel. This is then sold for smelting. This means that 100 percent of the valuable metals are returned to the raw material cycle. On the other hand, we receive the decoated ABS plastic that we use to manufacture new parts. Here, we use the material directly on site in our plastic injection molding plant and can thus close the material cycle at the site.

What further steps is Hansgrohe planning to take to further optimize the recycling process and sustainability in production?

Zapf: Together with the Hansgrohe Executive Board, our "Green Company" team has defined three fields of action: "Hansgrohe protects water cycles", "Hansgrohe protects the climate" and "Hansgrohe becomes part of the circular economy". A wide variety of initiatives are derived from this - from the product portfolio with water-saving mixers and showers to the development of environmentally friendly, plastic-free packaging, the use of solar and wind energy or recycling in production. We are all constantly working on our sustainable management with great commitment – new ideas are added almost daily and project progress is constantly being made. For example, we are considering whether it will be possible in the long term to reintroduce used products into the material cycle. However, this task is extremely complex, as a wide variety of materials are used in a complete product. But challenges are there to be tackled. At the beginning of our project with the plastics recycling plant, we were not sure whether we would achieve our goal. But the successful cooperation with ImpulsTec naturally gives us confidence for further projects of this kind.