Quick-drying coating systems for gearboxes, pumps and motors
Increasing energy efficiency in coating processes
Energy efficiency is not just the key to the energy transition but, in the area of mechanical engineering, it also results in a more efficient production and increases competitiveness. FreiLacke, the Black Forest-based manufacturer of innovative system coatings, has now developed a new coating system for gearboxes, pumps and electric motors that is ready to be launched. It significantly reduces the time the coating needs to dry as well as the energy required during the drying process. "Another criterion for the development of our new 2K-HighSolid-PUR system was its very good corrosion protection, which, together with a coordinated primer, meets the requirements of DIN EN ISO 12944", explains Andreas Morlock, head of the Development and Application Technology Industrial Coatings group of the coating manufacturer from Germany's Baden region. "At the same time, we wanted to guarantee a good chemical resistance against the technical operating liquids typically used in mechanical engineering, such as hydraulic oils, gear oils, coolants and lubricants as well as cleaning agents and solvents."
Reducing throughput times with HighSolid-PUR coating systems
The HighSolid (HS) primer UR1407 and the HS top coat UR1984 are the result of a special development project for gearboxes, pumps and motors. Due to the very quick drying kinetics the coated parts reach packaging strength and/or assembling stability after only 60 to 90 minutes at room temperature. Because a dryer is not needed, the energy savings are substantial. The components can then be processed or shipped immediately. Optionally, the drying time can be further reduced by using a coating dryer.
High adhesion, resistance and good corrosion protection
Due to its high level of adhesion, chemical resistance and good corrosion protection ability, the HS top coat UR1984 can be applied in a single layer to many workpieces. The use of a primer for low corrosion protection categories (up to a max. C3M) is not required. "If, however, corrosion categories C4 and C5 – according to DIN EN ISO 12944 – apply due to higher stresses outdoors, a multi-coating structure must be used," explains Harald Kämpf, project manager of the GPM Sales Industry Group.
Quick and flexible coating changes are possible
The HS top coat UR1984 has very good adhesion properties on different substrates. Furthermore, the adhesive strength on difficult substrates such as stainless steel or aluminium can be improved further by using the HS primer UR1407. The HS top coat UR1984 is resistant against a variety of chemicals and operating materials. "Due to the high compatibility of the two coating systems, the primer UR1407 and the top coat UR1984 can be processed on the same system," says coating specialist Andreas Morlock. "Both products are crosslinked with the same curing agent using the same mixing ratio. This makes a quick and flexible coating change at the coating system possible." Due to a pot life of no more than 90 minutes, processing with a 2C system is recommended. All standard coating processes are suited for the application.
Epoxy systems as alternatives to PUR systems
Modern UltraHighSolid (UHS) epoxy systems can be used when the application of PUR systems is not possible because the process is supposed to be isocyanate-free. For these types of individual cases, the UHS coating systems ER1957 (top coat) and ER1945 (structure coating) as well as ER1936 (primer) were newly developed.
Achieving top corrosion protection
In case of particularly high demands on the corrosion protection, the UHS primer ER1936 with a solids content of 80% can be used. In a two-layer structure, ER1936 can be used with a PUR top coat, or as a one-layer variant for fittings and pumps. "This coating system features a good spray adhesion, high stability and a pot life of between 3 to 4 hours, depending on the ambient temperature," summarises Harald Kämpf. In practice, one-layer coating structures with high dry coating thicknesses of up to 350 µm can be achieved.
Use of renewable raw materials
Particular attention was paid to the selection of raw materials during the development of this epoxy primer. By using renewable raw materials, it was possible to formulate UHS curing agent HE0016 in such a way that the irritation caused by amine hardeners was reduced significantly. What is especially noteworthy is that both ER1936H and curing agent HE0016 were brought into series production without the use of any reactive thinners.
The potential areas of application of these modern 2C PUR and 2C epoxy resin coating systems can be found predominantly in the area of drive technology when coating gearboxes, hydraulic motors, electric motors, pumps, actuators, fans, fittings, etc. It can be utilised wherever a VOC-uitable coating system is supposed to be used for energy-efficient, high quality and efficient coatings with short cycle times.