Improved UHS coating formulations for agricultural machinery technology

To meet the increased demands on the surfaces of agricultural machinery, a coatings manufacturer improved the formulations of its UltraHighSolid systems (UHS) for agricultural machinery. This enabled VOC emissions and drying times to be reduced.

A customer in the agricultural machinery sector has been using the system coating concept from FreiLacke for years. However, higher-quality surfaces are also increasingly in demand in this segment. Without further ado, FreiLacke improved the formulations in the wet paint structure and reduced the density of the products, which led to a sustainable reduction in VOC emissions and a significant acceleration of drying times.

Disc harrows, cultivators, knife rollers - the spectrum of agricultural machinery manufacturer Horsch is large. The company, headquartered in Schwandorf in the Upper Palatinate, looks back on a history of around forty years and first became known for its three-wheel tractors and equipment for minimum tillage. Today, Horsch manufactures agricultural technology as well as solutions for tillage, seeding and crop protection. In 2007, the company opened its first external production facility in Ronneburg: Series products such as the Pronto DC, Terrano FX and Joker CT/RT are manufactured here in Thuringia. The plant includes a large painting and assembly center, where two painting lines ensure high-quality and stable coloring.

Horsch is one of the few suppliers of high-gloss surfaces, with which the company aims to meet the increased demands on the surfaces of agricultural machinery. "Accordingly, painting is becoming increasingly important in the agricultural machinery sector," says Rudolf Obermeier, area foreman for surface coating at Horsch in Schwandorf. When he moved to Horsch in 2015, optimizing the surfaces was directly on the agenda. "The stability and edge coverage of the paint previously used was not satisfactory. In addition to a wide variety of frames and small parts, we also paint many large surfaces, such as on the tanks, and for this we need very good and reliable spray mist absorption," he explains. At the time, it was also important to achieve a sustainable reduction in VOC emissions.

Before joining Horsch, Obermeier had already worked with the manufacturer FreiLacke for many years. He brought the Black Forest-based coatings manufacturer into the picture, which subsequently relaunched one of its UltraHighSolid systems for agricultural machinery, significantly reducing emissions. After this promising start, Horsch decided to switch to the FreiLacke UR1937HRU735 system in combination with UR1409GH3307. A positive side effect: The Black Forest manufacturer was able to convince with its system paint concept and guarantee an identical red tone - the so-called Horsch red - in both powder and liquid paint quality.

However, because a coating from the automotive sector had previously provided a particularly high-quality finish, the course of the FreiLacke system was repeatedly questioned, reports Stefan Kritzer, Sales Manager Vehicle Construction at coating manufacturer FreiLacke. And so the Black Forest company was asked to improve it as far as possible. The development and application technology teams at FreiLacke were happy to accept this challenge. They optimized the formulations until the desired result was achieved. Obermeier and his team were thrilled: "The flow improvement and a further reduction in solvent emissions have been impressively achieved with the PU primer UR1933HRU735 and the PU topcoat UR1447NH3307." A successful large-scale trial was already carried out in November 2020, and Horsch then switched to the new formulations in February 2021.

The optimized coating structure is ideally suited for industrial goods and construction machinery of all kinds. Both components, i.e. primer and topcoat, contain solvents and are based on polyurethane / isocyanate-crosslinking polyacrylate resin as binder. The topcoat is available in "high gloss" quality. In addition to the required high level of corrosion protection, the solventborne primer offers good adhesion to various substrates - these include steel, also blasted or iron-phosphated, and stainless steel. The matching UHS topcoat UR1447N is characterized by good flow and equally good application properties. Its processing window after hardener addition is max. two hours at 20 °C. The solid volume after hardener addition is 455 ml / kg (± 10).

The new formulations have now been in successful use for more than two years. Not only are the sites highly satisfied - the environment also benefits from the significantly reduced solvent emissions. In addition, the coating system has significantly shortened the cycle time: It is no coincidence that the Horsch Leeb site in Landau a. d. Isar will also switch to the proven system from September 2023. And regardless of whether they are powder-coated or painted: The agricultural machines will shine in the desired Horsch red in a surface that is in no way inferior to an automotive finish. (OM-09/23)