Toothbrushes. We all know them, we all use them. Some of us use them right, others get it wrong, but most of us use them twice as long as we should. Did you know that dentists recommend using a new one at least every three months? Or earlier, if they’re wearing out or if you’ve had a cold. Assuming ideal use, that’s four toothbrushes a year each for around 83 million people in Germany. Let’s do the math: 332 million toothbrushes end up in the trash. Globally, we are looking at billions and valuable resources that are lost forever. The new toothbrush developed from ZAHORANSKY and Evonik is set to break this cycle: It’s 100 percent recyclable.
Conventional toothbrushes have a continuous handle or parts that snap together. Then there’s electric models where you only replace the top bit. The bristles are added in one of two ways: either with or without anchoring. In the latter case, they are bent into a U shape and held in place in the brush head with a small bit of metal. A toothbrush is therefore always composed of several components that machines such as ZAHORANSKY’s CUBE can manufacture in a fully automatic way in any design or feature variant.
But when it comes to recycling, all of them will suffer the same fate: It’s all but impossible, or at least very difficult, to separate the different materials later and so, the whole brush ends up disposed of in the household garbage. One alternative is to use brushes with replaceable heads. These allow you to replace only the heads or even only the bristles. But we’re still producing plastic waste, even if it is less.
Key part of ZAHORANSKY’s sustainability concept
ZAHORANSKY has been investigating sustainability for a while now—both for products and for packaging. Only last November 2022, ZAHORANSKY AG and KOCH Pac-Systeme GmbH began working closely together in the blister packaging field on technology and sales issues. This new cooperation focuses on providing sustainable, environmentally-friendly packaging solutions in the personal care sector. Robert Dous, Managing Director ZAHORANSKY Automation & Molds and Chief Sales Officer ZAHORANSKY GROUP, says: ‘It’s a perfect fit in that we can also offer our customers the option of sustainable products. This also includes, for example, processing alternative materials for toothbrush bodies made of bamboo and wood.’
100 percent recyclable: The mono-material toothbrush by VESTAMID®
ZAHORANSKY teamed up with Evonik for the K trade fair in 2022 to kick off an innovation project for production of a bio-based toothbrush. It uses one of Evonik’s granulates as the material. When ZAHORANSKY’s stocks needed for prototyping toothbrushes ran low, they got in touch with Johannes-Florian Krampe, Manager Filaments & New Business Development | High Performance Polymers at Evonik. He told ZAHORANSKY about the opportunities offered by long-chain polyamides traded under the brand VESTAMID®. Among them, we find polyamide-12, or PA 12 for short. This material is used as a high-performance plastic for toothbrush bristles in premium products, yet is equally suitable for the other parts of a toothbrush. Krampe says: ‘Because they’re made from a single material, these models would be fully recyclable. After all, that is what we should be aiming for as a society: Recyclable products that can be used to build a circular economy.’ ZAHORANSKY and Evonik took this idea further and decided to develop a first prototype made of PA 12 for presentation at the K trade fair 2022.
From idea to finished product in only five months
The first challenge was the tight schedule. From the initial idea in June 2022 until the K fair opened its doors in October, there were only five months. And Evonik still needed to actually produce the granulate. With regard to practical implementation, Ingo Kumpf, Head of Research & Development with ZAHORANSKY, tells us: ‘We wanted the entire toothbrush, so filaments as well as handle, to consist of a purely bio-based material. But so far, we’d never processed this material, not in an injection press for handle production nor in a tufting machine that separates the filaments and adds them to the handle. Our experience from many past projects has shown us that during processing we often uncover a surprise or two. And that the injection molding process needs to be adapted to the new materials first.’
Evonik managed to supply the dyed granulate at very short notice as the filament supplier PMM from Mexico still had a small production window available. This enabled the filaments to be added to the handle in time, despite the long delivery distances. The materials proved to be easy to process in both cases and the prototypes were actually ready in time for the K fair with one small catch in terms of recyclability.
A necessary compromise for tufting
Because of the tight deadline, the ‘trade fair toothbrush’ still had to be tufted using anchor technology. This was because those were the only machines available. The goal, however, is still to produce a version without a metal anchor. ZAHORANSKY is planning further development steps in 2023 to produce a purely bio-based toothbrush. After use, this mono-material toothbrush can be recycled as part of a circular economy.
Looking to the future
According to Ingo Kumpf, ‘The PA 12 material is well suited for manufacturing handles and filaments, with comparably positive processing properties to the common fossil-based materials such as PA6.12 or PBT.’ This means that PA 12 has the potential for use in other bio-based products, in turn making fossil raw materials redundant for such products. Exploitation of global resources is reduced thereby making the mountains of garbage that much smaller in the future. Now that they know how PA 12 works and is processed, ZAHORANSKY can better advise its customers on sustainable products and corresponding holistic solutions.
Background information about VESTAMID® eCO
A sustainable material is used to improve the toothbrush’s ecological footprint: VESTAMID® eCO, a polyamide-12 (PA 12). Evonik’s eCO range consists of renewable or circular raw materials. As a result, emissions of the greenhouse gas carbon dioxide will already be significantly reduced in the manufacturing process. This is achieved by the mass balance approach and means that the share of renewable or recyclable raw materials is determined along the entire value chain. A neutral body then checks this across all stages of production. For more information, visit: https://www.vestamid.com/en