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  • Bühler AG, Transitioning to Hydro Paints

Transitioning to hydro coatings: Improved worker safety and environmental performance with high performance water-based coatings

Away from solvent-based coatings: Bühler AG spent two years researching, formulating and testing with Brillux Industrial Coatings. The Swiss technology group is now coating its machines for food, non-food and die-casting applications with the new, extremely robust water-based products at two of its 30 production sites worldwide – using existing coating systems.

“At Bühler AG, our activities are focused on people, the environment and the future,” emphasizes Thomas Schmidt, Head of Surface Treatment Wet Coating and Powder Coating at Bühler AG in Uzwil. “We put this focus into practice. That’s why we were looking for a solvent-free alternative for coating the systems we manufacture – one that is functionally impressive, runs on our existing systems, and at the same time protects the environment and the health of our employees in the coating departments.” The company is a major player in the fields of technology and process engineering for food and animal feed production, high-performance die casting machines for the automotive and aerospace industries, and grinding and dispersion systems, e.g. for the production of paints and coatings, printed products, and solar modules. The Bühler Group operates in 140 countries around the world, employed some 12,500 people in 2021 and generated sales of 2.7 billion Swiss francs in the same year. When a group of this size switches from solvent-based to water-based wet coatings, the effect is noticeable.

machine without paint

Different substrates, shapes and finishes: the complexity of this Bühler die casting machine is a challenge for painters and places high demands on the corresponding wet paint system.

machine parts with primer

two coats of primer with the optimally matched water-based product: Hydro-2K-EP Flex Primer 5719 from Brillux Industrial Coatings meets the high specifications for corrosion protection and separating agent resistance for Bühler die casting solutions.

coating process

Different application methods are used depending on the component requirements. This Bühler die casting machine is coated using the Airmix process.

coating process

Different application methods are used depending on the component requirements. This Bühler die casting machine is coated using the Airmix process.

area of pretreatment

Efficient: Even in the area of pretreatment, which in this case is performed manually for large assemblies, no changes were necessary when Bühler switched to water-based paints. The previous cleaning processes could simply continue to be used.

cleaning process

The established workflow also simply continued in the bath cleaning area. Bühler pre-treats all components with the same cleaning process, regardless of whether they are later coated with powder or wet paint. This results in further time and cost savings.

Required: a single coating system for all applications

The challenges that the company faced when switching to hydro coatings were no less significant. “Our aim was to cover all our business areas with a single coating system,” recalls Mirjam Rüegg. As project manager at Bühler AG, she was responsible for the transition process. “The requirements for the respective system coating are very high in each of our business units, but they could hardly be more different. Coatings for food systems naturally require food safety approval. For die casting machines, we have the highest requirements for separating agent resistance and corrosion protection. For paint systems, on the other hand, the coating must be resistant to solvents and chemicals.”

  • Together with Brillux Industrial Coatings, Bühler has exclusively defined a total of 14 different color shades in various degrees of gloss. Of course, this color variety is also available in other color collections (RAL, NCS, Scala, etc.) as well as for the new water-based coatings.

Wanted: the optimum formulation for the highest requirements

Bühler AG has defined strict quality criteria for wet and powder coatings in its own strict test standard. Mirjam Rüegg and her colleagues approached Brillux Industrial Coatings with this test standard and the desire for the perfect hydro coating. The coatings manufacturer has been working with Bühler AG as a system supplier for wet and powder coatings since 2003. “We first developed the optimal individual formulation for the hydro system of the Bühler systems in the laboratory,” says Dr. Rolf Roesmann. He heads the research and development department for wet coatings systems at Brillux Industrial Coatings in Unna, Germany. “After the initial successful tests, we went straight to field trials together.

Tested: Achieving the goal in two practical phases

At two Buhler production sites – at the headquarters in Uzwil, Switzerland, and in Zamberk, Czech Republic – initially only the top coat was replaced by the newly developed water-based two-component system, and the existing coating and pretreatment systems as well as the dryers were upgraded with minimal investment. The focus was on optimizing the surface quality of the new coating. After thorough and ongoing testing of the results and employee training, the entire water-based coating assembly at the Uzwil site was replaced with a new primer. In April 2022, Uzwil became the first Bühler production site to go into series production with a completely solvent-free coating. “The fact that we were able to complete the conversion within two years is certainly also due to the partnership and close support from Brillux Industrial Coatings,” emphasizes Thomas Schmidt. “Dr. Roesmann and our technical advisor at Brillux, Holger Schroth, were always available to us – whether on site or in productive online feedback sessions. In addition to the functional aspects of the new coating, this also applied to the jointly developed new color concept for the coating. Brillux Industrial Coatings offers products with a wide range of colors and can deliver customized wet coating systems quickly and flexibly.

  • assembled and painted machine

Successful: a project with a multiplier effect

Mirjam Rüegg is also delighted with the success of the project. “I find it sensational that the two newly developed Brillux products Hydro-2K-EP Flex Primer 5719 and Hydro-2K-PUR Topcoat 5860/5861 meet all quality requirements according to UAB-24002 and are now available to the entire market as high-performance water-based coatings.

The Buhler Group will gradually introduce the hydro system assembly for all its machine coatings at all 30 production sites worldwide and will also bring its suppliers on board. Uzwil is already reaping significant benefits from this sustainable solution – and not only because the VOC tax of over three Swiss francs per liter on solvent-based paints is no longer applicable.

“Our industrial coaters are now familiar with the new water-based, process-safe system,” explains Thomas Schmidt. “They report enthusiastically about the new, pleasant feeling in the spray booth and confirm that we made the right decision in terms of health protection.”

Another positive aspect for the employees and the company is that the changeover to water-based coatings has not changed the system peripherals, the workflow or the high surface quality of the paint finish. With minimal, almost cost-neutral interventions such as cleaning and changing seals on the existing coating systems, production could continue seamlessly. Without a doubt: under these conditions, the switch to hydro coating is not only sustainable, but also economically efficient.


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More about the Hydro-2K system coatings from Brillux Industrial Coatings:

Bühler AG

Bühler AG

Bühler is a versatile company – with its solutions for the food and mobility sectors, it is highly likely that you have already come into contact with technologies from the company.